Covid-19 living Data

COVID-19 vaccine effectiveness
(Randomized evidence)

Methods

Latest news:Last search date July 30, 2023. No further screening is planned after this date. Extraction is ongoing for all pending studies.

A list of studies pending extraction is available here.

meta-COVID

Perform your own analysis using COVID-NMA data for prime vaccination (last search date 14/12/2022), create and download your forest plots by clicking below:

Vaccine types

COVID-19 BOOSTER DOSE VACCINATION: updated daily

Vaccine efficacy, immunogenicity and safety of booster vs no booster (tables)

Reference	Type of prime vaccination	Prime schedule	Intervention 1	Intervention 2	Follow up days	Participants	GMT1(N1)	GMT2(N2)	GMR [95% CI]	Evaluated by
	A	B	C	D	E	Overall
Hall VG, 2021	RNA based vaccine	mRNA-1273	Boost mRNA-1273	Placebo	28	Transplant recipients	3,145 (60)	86 (57)	36.5 [ 12.9, 94]	Roche Elecsys
Vadrevu KM, 2022	Inactivated virus	BBV152	Boost BBV152	Placebo	28	Adolescents and adults	7,013 (80)	4,294 (87)	1.56 [1.06, 2.28]	ELISA

Immunogenicity
Geometric mean titre specific antibodies
Geometric mean titre neutralization assay against -wild type

Reference	Type of prime vaccination	Prime schedule	Intervention 1	Intervention 2	Follow up days	Participants	GMT1(N1)	GMT2(N2)	GMR [95% CI]	Evaluated by	Risk of bias
											A	B	C	D	E	Overall
Vadrevu KM, 2022	Inactivated virus	BBV152	Boost BBV152	Placebo	28	Adolescents and adults	746 (80)	101 (87)	7.41 [2.96, 18.51]	PRNT
Zhang Y, 2023	Inactivated virus	CoronaVac	Boost ChAdTS-S	Placebo	14	Adults	290 (48)	5 (46)	56.8 [43.6, 74.1]	Micro-neutralisation assay
Zhang Y, 2023	Inactivated virus	CoronaVac	Boost RQ3013	Placebo	14	Adults	950 (46)	5 (46)	190.9 [145.8, 249.9]	Micro-neutralisation assay
Zhang Y, 2023	Inactivated virus	CoronaVac	Boost ZR202-CoV	Placebo	14	Adults	635 (47)	5 (46)	120.8 [92.6, 157.6]	Micro-neutralisation assay
Zhang Y, 2023	Inactivated virus	CoronaVac	Boost CoronaVac	Placebo	14	Adults	75 (46)	5 (46)	15.1 [11.5, 19.8]	Micro-neutralisation assay
Munro A, 2021 e	Non replicating viral vector	ChadOx1	Boost mRNA1273	Placebo	28	Adults, elderly, health care workers	2,368 (97)	80 (101)	26.98 [21.88, 33.26]	PNA
Munro A, 2021 e	Non replicating viral vector	ChadOx1	Boost CVnCov	Placebo	28	Adults, elderly, health care workers	373 (99)	80 (101)	5.06 [4.11, 6.23]	PNA
Munro A, 2021 e	Non replicating viral vector	ChadOx1	Boost BNT162b2 half dose	Placebo	28	Adults, elderly, health care workers	1,344 (103)	80 (101)	15.14 [12.32, 18.60]	PNA
Munro A, 2021 c	Non replicating viral vector	ChadOx1	Boost BNT162b2	Placebo	28	Adults, elderly, health care workers	1,621 (93)	70 (91)	21.58 [16.93, 27.51]	PNA
Munro A, 2021 c	Non replicating viral vector	ChadOx1	Boost VLA2001	Placebo	28	Adults, elderly, health care workers	202 (89)	70 (91)	2.68 [2.10, 3.43]	PNA
Munro A, 2021 c	Non replicating viral vector	ChadOx1	Boost VLA2001 half dose	Placebo	28	Adults, elderly, health care workers	147 (95)	70 (91)	2.01 [1.57, 2.55]	PNA
Munro A, 2021 c	Non replicating viral vector	ChadOx1	Boost Ad26.COV2.S	Placebo	28	Adults, elderly, health care workers	563 (95)	70 (91)	6.85 [5.37, 8.73]	PNA
Munro A, 2021 b	RNA based vaccine	BNT162b2	Boost ChadOx1	Placebo	28	Adults, elderly, health care workers	950 (98)	157 (111)	6.01 [4.87, 7.41]	PNA
Munro A, 2021 b	RNA based vaccine	BNT162b2	Boost Novavax	Placebo	28	Adults, elderly, health care workers	766 (94)	157 (111)	5.39 [4.35, 6.67]	PNA
Munro A, 2021 b	RNA based vaccine	BNT162b2	Boost Novavax half dose	Placebo	28	Adults, elderly, health care workers	606 (89)	157 (111)	3.50 [2.81, 4.36]	PNA
Munro A , 2021 a	Non replicating viral vector	ChadOx1	Boost ChadOx1	Placebo	28	Adults, elderly, health care workers	193 (98)	85 (90)	2.47 [1.96, 3.11]	PNA
Munro A , 2021 a	Non replicating viral vector	ChadOx1	Boost Novavax	Placebo	28	Adults, elderly, health care workers	727 (87)	85 (90)	8.86 [7.00, 11.22]	PNA
Munro A , 2021 a	Non replicating viral vector	ChadOx1	Boost Novavax	Boost ChadOx1	28	Adults, elderly, health care workers	727 (87)	193 (98)	8.86 [7.00, 11.22]	PNA
Munro A , 2021 a	Non replicating viral vector	ChadOx1	Boost Novavax half dose	Boost ChadOx1	28	Adults, elderly, health care workers	470 (86)	193 (98)	5.89 [4.64, 7.46]	PNA
Munro A , 2021 a	Non replicating viral vector	ChadOx1	Boost Novavax half dose	Placebo	28	Adults, elderly, health care workers	470 (86)	85 (90)	5.89 [4.64, 7.46]	PNA
Munro A, 2021 f	RNA based vaccine	BNT162b2	Boost mRNA1273	Placebo	28	Adults, elderly, health care workers	2,019 (91)	175 (98)	12.04 [9.95, 14.58]	PNA
Munro A, 2021 f	RNA based vaccine	BNT162b2	Boost CVnCov	Placebo	28	Adults, elderly, health care workers	487 (91)	175 (98)	2.57 [2.13, 3.12]	PNA
Munro A, 2021 f	RNA based vaccine	BNT162b2	Boost BNT162b2 half dose	Placebo	28	Adults, elderly, health care workers	1,339 (92)	175 (98)	6.91 [5.70, 8.37]	PNA
Munro A, 2021 d	RNA based vaccine	BNT162b2	Boost BNT162b2	Placebo	28	Adults, elderly, health care workers	1,789 (95)	205 (93)	8.35 [6.88, 10.14]	PNA
Munro A, 2021 d	RNA based vaccine	BNT162b2	Boost VLA2001	Placebo	28	Adults, elderly, health care workers	289 (91)	205 (93)	1.38 [1.14, 1.68]	PNA
Munro A, 2021 d	RNA based vaccine	BNT162b2	Boost VLA2001 half dose	Placebo	28	Adults, elderly, health care workers	234 (87)	205 (93)	1.22 [1.00, 1.49]	PNA
Munro A, 2021 d	RNA based vaccine	BNT162b2	Boost Ad26.COV2.S	Placebo	28	Adults, elderly, health care workers	1,441 (75)	205 (93)	7.84 [6.37, 9.64]	PNA
Wang X-Y, 2022	Inactivated virus	BBIBP-CorV or CoronaVac	Boost V-01	Placebo	14	Healthy adults	1,453 (199)	157 (221)	NR	Live SARS-CoV-2 neutralization assay.
Thuluva S, 2023 a	Non replicating viral vector	ChAdOx1	Boost BECOV2	Boost Placebo	28	Adults	6,317 (156)	1,877 (52)	*3.37 [2.00, ]**	Plaque Reduction Neutralization Titer (PRNT)

Number of patients analyzed in intervention 1; N2: Number of patients analyzed in intervention 2; GMT1: Geometric mean titre for intervention 1; GMT2: Geometric mean titre for intervention 2; N1GMR: Geometric mean ratio

Geometric mean titre neutralization assay- omicron

Reference	Type of prime vaccination	Prime schedule	Intervention 1	Intervention 2	Follow up days	Participants	GMT1(N1)	GMT2(N2)	GMR [95% CI]	Evaluated by	Risk of bias
											A	B	C	D	E	Overall
Zhang Y, 2023	Inactivated virus	CoronaVac	Boost ChAdTS-S	Placebo	14	Adults	41 (48)	4 (46)	10.3 [7.6, 14.0]	Micro-neutralisation assay
Zhang Y, 2023	Inactivated virus	CoronaVac	Boost RQ3013	Placebo	14	Adults	247 (46)	4 (46)	62.4 [45.8, 85.1]	Micro-neutralisation assay
Zhang Y, 2023	Inactivated virus	CoronaVac	Boost ZR202-CoV	Placebo	14	Adults	104 (47)	4 (46)	26.0 [19.1, 35.4]	Micro-neutralisation assay
Zhang Y, 2023	Inactivated virus	CoronaVac	Boost CoronaVac	Placebo	14	Adults	8 (46)	4 (46)	2.0 [1.5, 2.7]	Micro-neutralisation assay
Hannawi S, 2022	Inactivated virus	BBIBP-CorV	Boost SCTV01C 20mcg	Placebo		Adults	840 (74)	58 (72)	14.4 [10.3, 20.2]	Plaque Reduction Neutralization Assay (PRNT50)
Hannawi S, 2022	Inactivated virus	BBIBP-CorV	Boost SCTV01C 40mcg	Placebo		Adults	901 (75)	58 (72)	15.0 [10.7, 21.1]	Plaque Reduction Neutralization Assay (PRNT50)
Munro A, 2021 d	RNA based vaccine	BNT162b2	Boost BNT162b2	Placebo	28	Adults, elderly, health care workers	0 (95)	0 (93)	NR	NR
Munro A, 2021 d	RNA based vaccine	BNT162b2	Boost VLA2001	Placebo	28	Adults, elderly, health care workers	0 (91)	0 (93)	NR	NR
Munro A, 2021 d	RNA based vaccine	BNT162b2	Boost VLA2001 half dose	Placebo	28	Adults, elderly, health care workers	0 (87)	0 (93)	NR	NR
Munro A, 2021 d	RNA based vaccine	BNT162b2	Boost Ad26.COV2.S	Placebo	28	Adults, elderly, health care workers	0 (75)	0 (93)	NR	NR
Thuluva S, 2023 a	Non replicating viral vector	ChAdOx1	Boost BECOV2	Boost Placebo	28	Adults	79 (156)	0 (52)	NR	Pseudovirus Neutralization Assay (PNA)

Safety
Serious adverse events

Reference	Type of prime vaccination	Prime schedule	Intervention 1	Intervention 2	Follow up months	Participants	r1/N1	r2/N2	RR [95% CI]	Risk of bias
										A	B	C	D	E	Overall
Vadrevu KM, 2022	Inactivated virus	BBV152	Boost BBV152	Placebo	1	Adolescents and adults	0 / 80	0 / 87	NR
Tabarsi P, 2022	Any COVID-19 vaccine	Any Covid-19 vaccine	Boost SpikoGen	Placebo	0.5	Adults	0 / 250	0 / 50	NR
Zhang Y, 2023	Inactivated virus	CoronaVac	Boost ChAdTS-S	Placebo	3	Adults	0 / 48	3 / 47	0.14 [0.01 - 2.63]
Zhang Y, 2023	Inactivated virus	CoronaVac	Boost RQ3013	Placebo	3	Adults	0 / 47	3 / 47	0.14 [0.01 - 2.69]
Zhang Y, 2023	Inactivated virus	CoronaVac	Boost ZR202-CoV	Placebo	3	Adults	0 / 47	3 / 47	0.14 [0.01 - 2.69]
Zhang Y, 2023	Inactivated virus	CoronaVac	Boost CoronaVac	Placebo	3	Adults	0 / 46	3 / 47	0.15 [0.01 - 2.74]
Moreira E D, 2022	RNA based vaccine	BNT162b2	Boost BNT162b2	Placebo	2.5	Adults and adolescents	16 / 5055	24 / 5020	0.66 [0.35 - 1.24]
Sung J, 2022	Any COVID-19 vaccine	2 doses BNT162b2 or BBIBP	Boost Recombinant inactiv Bacillus subtilis spores	Boost active adjuvant	1.2	Healthy adults	0 / 9	0 / 7	NR
Hannawi S, 2022	Inactivated virus	BBIBP-CorV	Boost SCTV01C 20mcg	Placebo	1	Adults	0 / 79	0 / 75	NR
Hannawi S, 2022	Inactivated virus	BBIBP-CorV	Boost SCTV01C 40mcg	Placebo	1	Adults	0 / 80	0 / 75	NR
Munro A, 2021 e	Non replicating viral vector	ChadOx1	Boost mRNA1273	Placebo	2.7	Adults, elderly, health care workers	1 / 112	0 / 114	3.05 [0.13 - 74.16]
Munro A, 2021 e	Non replicating viral vector	ChadOx1	Boost CVnCov	Placebo	2.7	Adults, elderly, health care workers	0 / 119	0 / 114	NR
Munro A, 2021 e	Non replicating viral vector	ChadOx1	Boost BNT162b2 half dose	Placebo	2.7	Adults, elderly, health care workers	0 / 116	0 / 114	NR
Munro A, 2021 c	Non replicating viral vector	ChadOx1	Boost BNT162b2	Placebo	2.7	Adults, elderly, health care workers	0 / 106	1 / 105	0.33 [0.01 - 8.01]
Munro A, 2021 c	Non replicating viral vector	ChadOx1	Boost VLA2001	Placebo	2.7	Adults, elderly, health care workers	3 / 109	1 / 105	2.89 [0.31 - 27.34]
Munro A, 2021 c	Non replicating viral vector	ChadOx1	Boost VLA2001 half dose	Placebo	2.7	Adults, elderly, health care workers	0 / 111	1 / 105	0.32 [0.01 - 7.66]
Munro A, 2021 c	Non replicating viral vector	ChadOx1	Boost Ad26.COV2.S	Placebo	2.7	Adults, elderly, health care workers	1 / 108	1 / 105	0.97 [0.06 - 15.34]
Munro A, 2021 b	RNA based vaccine	BNT162b2	Boost ChadOx1	Placebo	2.7	Adults, elderly, health care workers	0 / 109	1 / 118	0.36 [0.01 - 8.76]
Munro A, 2021 b	RNA based vaccine	BNT162b2	Boost Novavax	Placebo	2.7	Adults, elderly, health care workers	1 / 114	1 / 118	1.04 [0.07 - 16.35]
Munro A, 2021 b	RNA based vaccine	BNT162b2	Boost Novavax half dose	Placebo	2.7	Adults, elderly, health care workers	2 / 112	1 / 118	2.11 [0.19 - 22.91]
Munro A , 2021 a	Non replicating viral vector	ChadOx1	Boost ChadOx1	Placebo	2.7	Adults, elderly, health care workers	1 / 111	0 / 109	2.95 [0.12 - 71.54]
Munro A , 2021 a	Non replicating viral vector	ChadOx1	Boost Novavax	Placebo	2.7	Adults, elderly, health care workers	0 / 115	0 / 109	NR
Munro A , 2021 a	Non replicating viral vector	ChadOx1	Boost Novavax	Boost ChadOx1	2.7	Adults, elderly, health care workers	0 / 115	1 / 111	0.32 [0.01 - 7.82]
Munro A , 2021 a	Non replicating viral vector	ChadOx1	Boost Novavax half dose	Boost ChadOx1	2.7	Adults, elderly, health care workers	0 / 108	1 / 111	0.34 [0.01 - 8.32]
Munro A , 2021 a	Non replicating viral vector	ChadOx1	Boost Novavax half dose	Placebo	2.7	Adults, elderly, health care workers	0 / 108	0 / 109	NR
Munro A, 2021 f	RNA based vaccine	BNT162b2	Boost mRNA1273	Placebo	2.7	Adults, elderly, health care workers	0 / 110	0 / 112	NR
Munro A, 2021 f	RNA based vaccine	BNT162b2	Boost CVnCov	Placebo	2.7	Adults, elderly, health care workers	1 / 106	0 / 112	3.17 [0.13 - 76.94]
Munro A, 2021 f	RNA based vaccine	BNT162b2	Boost BNT162b2 half dose	Placebo	2.7	Adults, elderly, health care workers	0 / 110	0 / 112	NR
Munro A, 2021 d	RNA based vaccine	BNT162b2	Boost BNT162b2	Placebo	2.7	Adults, elderly, health care workers	1 / 109	0 / 109	3 [0.12 - 72.84]
Munro A, 2021 d	RNA based vaccine	BNT162b2	Boost VLA2001	Placebo	2.7	Adults, elderly, health care workers	0 / 110	0 / 109	NR
Munro A, 2021 d	RNA based vaccine	BNT162b2	Boost VLA2001 half dose	Placebo	2.7	Adults, elderly, health care workers	1 / 110	0 / 109	2.97 [0.12 - 72.18]
Munro A, 2021 d	RNA based vaccine	BNT162b2	Boost Ad26.COV2.S	Placebo	2.7	Adults, elderly, health care workers	0 / 106	0 / 109	NR
Wang X-Y, 2022	Inactivated virus	BBIBP-CorV or CoronaVac	Boost V-01	Placebo	NR	Healthy adults	6 / 5108	8 / 5110	0.75 [0.26 - 2.16]
Thuluva S, 2023 a	Non replicating viral vector	ChAdOx1	Boost BECOV2	Boost Placebo	6	Adults	0 / 156	0 / 52	NR

r1: Number of events in intervention 1, r2: Number of events in intervention 2, N1: Number of patients analyzed in intervention 1; N2: Number of patients analyzed in intervention 2.

All-cause mortality

Reference	Type of prime vaccination	Prime schedule	Intervention 1	Intervention 2	Follow up months	Participants	r1/N1	r2/N2	RR [95% CI]	Risk of bias
										A	B	C	D	E	Overall
Vadrevu KM, 2022	Inactivated virus	BBV152	Boost BBV152	Placebo	1	Adolescents and adults	0 / 80	0 / 87	NR
Toledo-Romani ME, 2022 b	Protein subunit	FINLAY-FR-2-25 mcg	Boost FINLAY-FR-1-50 mcg	Placebo	5.4	Adults	11 / 13883	24 / 14303	0.47 [0.23 - 0.96]
Moreira E D, 2022	RNA based vaccine	BNT162b2	Boost BNT162b2	Placebo	2.5	Adults and adolescents	0 / 5055	1 / 5020	0.33 [0.01 - 8.12]
Wang X-Y, 2022	Inactivated virus	BBIBP-CorV or CoronaVac	Boost V-01	Placebo	2	Healthy adults	0 / 5108	0 / 5110	NR
Sung J, 2022	Any COVID-19 vaccine	2 doses BNT162b2 or BBIBP	Boost Recombinant inactiv Bacillus subtilis spores	Boost active adjuvant	1.2	Healthy adults	0 / 9	0 / 7	NR
Zhang Y, 2023	Inactivated virus	CoronaVac	Boost ChAdTS-S	Placebo	3	Adults	0 / 48	0 / 47	NR
Zhang Y, 2023	Inactivated virus	CoronaVac	Boost RQ3013	Placebo	3	Adults	0 / 47	0 / 47	NR
Zhang Y, 2023	Inactivated virus	CoronaVac	Boost ZR202-CoV	Placebo	3	Adults	0 / 47	0 / 47	NR
Zhang Y, 2023	Inactivated virus	CoronaVac	Boost CoronaVac	Placebo	3	Adults	0 / 46	0 / 47	NR
Hannawi S, 2022	Inactivated virus	BBIBP-CorV	Boost SCTV01C 20mcg	Placebo	1	Adults	0 / 79	0 / 75	NR
Hannawi S, 2022	Inactivated virus	BBIBP-CorV	Boost SCTV01C 40mcg	Placebo	1	Adults	0 / 80	0 / 75	NR
Thuluva S, 2023 a	Non replicating viral vector	ChAdOx1	Boost BECOV2	Boost Placebo	6	Adults	0 / 156	0 / 52	NR

r1: Number of events in intervention 1, r2: Number of events in intervention 2, N1: Number of patients analyzed in intervention 1; N2: Number of patients analyzed in intervention 2.

Vaccine efficacy, immunogenicity and safety of booster VS booster (tables)

Immunogenicity
Geometric mean titre specific antibodies

Reference	Type of prime vaccination	Prime schedule	Intervention 1	Intervention 2	Follow up days	Participants	GMT Boost1 (N1)	GMT Boost2 (N2)	GMR [95% CI]	Evaluated by	Risk of bias
											A	B	C	D	E	Overall
Anderson E, 2022	RNA based vaccine	mRNA-1273	Boost 50 mcg mRNA-1273.351	Boost 25 mcg mRNA-1273.351 and 25 mcg mRNA-1273	14	Healthy volunteers	9,591 (25)	9,046 (22)	1.06 [0.78, 1.43]	4-plex Mesoscale Discovery (MSD) 10-plex assay.
Anderson E, 2022	RNA based vaccine	mRNA-1273	Boost 100 mcg mRNA-1273	Boost 25 mcg mRNA-1273.351 and 25 mcg mRNA-1273	14	Healthy volunteers	8,396 (41)	9,046 (22)	0.93 [0.69, 1.24]	4-plex Mesoscale Discovery (MSD) 10-plex assay.
Lien C, 2022 b	Protein subunit	MVC-COV1901	Boost MVC-COV1901+boost MVC-COV1901-Beta 15 mcg	Boost MVC-COV1901+boost MVC-COV1901	14	Adults including healthy or stable co-morbidities	28,179 (19)	21,078 (18)	1.33 [0.88, 2.01]	ELISA
Lien C, 2022 b	Protein subunit	MVC-COV1901	Boost MVC-COV1901+boost MVC-COV1901-Beta 25 mcg	Boost MVC-COV1901+boost MVC-COV1901	14	Adults including healthy or stable co-morbidities	21,638 (18)	21,078 (18)	1.02 [0.67, 1.55]	ELISA
Lien C, 2022 a	Protein subunit	MVC-COV1901	Boost MVC-COV1901-Beta 15 mcg	Boost MVC-COV1901	14	Adults including healthy or stable co-morbidities	32,938 (12)	25,879 (14)	1.27 [0.70, 2.83]	ELISA
Lien C, 2022 a	Protein subunit	MVC-COV1901	Boost MVC-COV1901-Beta 25 mcg	Boost MVC-COV1901	14	Adults including healthy or stable co-morbidities	43,209 (12)	25,879 (14)	1.66 [0.92, 3]	ELISA
Launay O, 2022	RNA based vaccine	BNT162b2	Boost MV B1.351	Boost BNT162b2	15	Adults including healthy or stable co-morbidities	2,241 (71)	2,405 (76)	0.93 [0.77, 1.13]	ELISA
Launay O, 2022	RNA based vaccine	BNT162b2	Boost MV D614	Boost BNT162b2	15	Adults including healthy or stable co-morbidities	1,875 (76)	2,405 (76)	0.78 [0.65, 0.94]	ELISA
Li J, 2022	Inactivated virus	CoronaVac	Boost Ad5-vectored	Boost Coronavac	14	Healthy adults	3,090 (96)	369 (102)	8.37 [6.52, 10.75]	ELISA
Cao Y, 2021	Inactivated virus	CoronaVac	Boost ZF2001	Boost CoronaVac	14	Healthcare workers	10,417 (81)	7,496 (40)	*1.38 [, ]*	ELISA
Nanthapisal S, 2022	Inactivated virus	2 doses of CoronaVac 21-28 days apart	Boost ChAdOx1-S standard dose	Boost ChAdOx1-S low-dose	14	Healthy adults	1,975 (209)	1,664 (209)	1.19 [1.07, 1.31]	ELISA
Shinkai M, 2022	RNA based vaccine	BNT162b2	Boost S-268019-b	Boost BNT162b2	28	Adults	48,465 (101)	55,215 (101)	0.87 [0.72, 1.06]	ELISA
Barda N, 2023	RNA based vaccine	BNT162b2	Boost BNT161b2-OMI 30mcg	Boost BNT162b2	30	Adults	4,774 (19)	5,409 (20)	0.88 [0.53, 1.48]	Automatic chemiluminescent microparticle immunoassay
Barda N, 2023	RNA based vaccine	BNT162b2	Boost BNT161b2-OMI 60mcg	Boost BNT162b2	30	Adults	5,959 (19)	5,409 (20)	1.10 [0.73, 1.65]	Automatic chemiluminescent microparticle immunoassay
Barda N, 2023	RNA based vaccine	BNT162b2	Boost BNT161b2-OMI 15/15mcg	Boost BNT162b2	30	Adults	7,487 (19)	5,409 (20)	1.38 [0.81, 2.37]	Automatic chemiluminescent microparticle immunoassay
Barda N, 2023	RNA based vaccine	BNT162b2	Boost BNT161b2-OMI 30/30mcg	Boost BNT162b2	30	Adults	4,672 (21)	5,409 (20)	0.86 [0.56, 1.33]	Automatic chemiluminescent microparticle immunoassay
Barda N, 2023	RNA based vaccine	BNT162b2	Boost BNT162b2 60mcg	Boost BNT162b2	30	Adults	3,611 (19)	5,409 (20)	0.67 [0.40, 1.11]	Automatic chemiluminescent microparticle immunoassay
Jin L, 2022	Inactivated virus	CoronaVac	Boost Ad5-vectored high dose	Boost CoronaVac	14	Healthy adults	6,175 (140)	670 (140)	9.21 [6.87, 12.35]	ELISA
Jin L, 2022	Inactivated virus	CoronaVac	Boost Ad5-vectored low dose	Boost CoronaVac	14	Healthy adults	4,625 (140)	670 (140)	6.9 [5.01, 9.50]	ELISA
Sablerolles R, 2022	Non replicating viral vector	Ad26.COV2.S	Boost m-RNA-1273	Boost Ad26.COV2.S	28	Healthcare workers	4,379 (112)	403 (106)	10.86 [8.22, 14.34]	Liaison SARS CoV-2 TrimericS IgG
Sablerolles R, 2022	Non replicating viral vector	Ad26.COV2.S	Boost BNT162b2	Boost Ad26.COV2.S	28	Healthcare workers	2,671 (111)	403 (106)	6.62 [4.93, 8.89]	Liaison SARS CoV-2 TrimericS IgG
Estephan L, 2023 a	Protein subunit	MVC-COV1901	Boost 1/2 MVC-COV1901	Boost MVC-COV1901	28	Adults	17,526 (75)	29,269 (75)	0.60 [0.46, 0.78]	ELISA
Estephan L, 2023 a	Protein subunit	MVC-COV1901	Boost 1/2 mRNA-1273	Boost MVC-COV1901	28	Adults	85,648 (75)	29,269 (75)	2.93 [2.23, 3.83]	ELISA
Estephan L, 2023 a	Protein subunit	MVC-COV1901	Boost ChAdOx1	Boost MVC-COV1901	28	Adults	54,372 (77)	29,269 (75)	1.86 [1.42, 2.43]	ELISA
Estephan L, 2023 c	RNA based vaccine	mRNA-1273	Boost MVC-COV1901	Boost 1/2 mRNA-1273	28	Adults	17,944 (33)	65,881 (44)	0.27 [0.21, 0.36]	ELISA
Estephan L, 2023 c	RNA based vaccine	mRNA-1273	Boost ChAdOx1	Boost 1/2 mRNA-1273	28	Adults	36,618 (41)	65,881 (44)	0.55 [0.43, 0.72]	ELISA
Estephan L, 2023 c	RNA based vaccine	mRNA-1273	Boost 1/2 MVC-COV1901	Boost 1/2 mRNA-1273	28	Adults	18,678 (41)	65,881 (44)	0.28 [0.22, 0.37]	ELISA
Estephan L, 2023 b	Non replicating viral vector	ChadOx1	Boost MVC-COV1901	Boost ChadOx1	28	Adults	11,469 (75)	4,924 (79)	2.33 [1.84, 2.95]	ELISA
Estephan L, 2023 b	Non replicating viral vector	ChadOx1	Boost mRNA-1273 (half dose)	Boost ChadOx1	28	Adults	55,310 (75)	4,924 (79)	11.23 [8.86, 14.24]	ELISA
Toback S, 2023	Inactivated virus	BBIBP-CorV	Boost NVX-CoV2373	Boost BBIBP-CorV	14	Healthy volunteers	388 (479)	215 (486)	1.8 [1.7, 1.9]	Chemiluminescence immunoassay (CLIA)

Geometric mean titre neutralization assay against -wild type

Reference	Type of prime vaccination	Prime schedule	Intervention 1	Intervention 2	Follow up days	Participants	GMT Boost1 (N1)	GMT Boost2 (N2)	GMR [95% CI]	Evaluated by	Risk of bias
											A	B	C	D	E	Overall
Anderson E, 2022	RNA based vaccine	mRNA-1273	Boost 50 mcg mRNA-1273.351	Boost 25 mcg mRNA-1273.351 and 25 mcg mRNA-1273	15	Healthy volunteers	2,111 (25)	2,435 (22)	0.87 [0.60, 1.24]	Neutralization assay (PsVN)
Anderson E, 2022	RNA based vaccine	mRNA-1273	Boost 100 mcg mRNA-1273	Boost 25 mcg mRNA-1273.351 and 25 mcg mRNA-1273	15	Healthy volunteers	2,842 (41)	2,435 (22)	1.17 [0.84, 1.62]	Neutralization assay (PsVN)
Al Kaabi N, 2022 b	Inactivated virus	BBIBP-CorV	Boost NVSI-06-08 4-6 months	Boost BBIBP-CorV 4-6 months	15	Healthy adults	3,142 (285)	197 (289)	15.96 [13.34, 19.08]	Live-virus neutralization assay
Al Kaabi N, 2022 b	Inactivated virus	BBIBP-CorV	Boost NVSI-06-08 7-9 months	Boost BBIBP-CorV 7-9 months	15	Healthy adults	4,908 (270)	505 (270)	9.72 [8.04, 11.77]	Live-virus neutralization assay
Al Kaabi N, 2022 b	Inactivated virus	BBIBP-CorV	Boost NVSI-06-08 >9 months	Boost BBIBP-CorV >9 months	15	Healthy adults	4,185 (286)	375 (278)	11.17 [9.44, 13.22]	Live-virus neutralization assay
Lien C, 2022 b	Protein subunit	MVC-COV1901	Boost MVC-COV1901+boost MVC-COV1901-Beta 15 mcg	Boost MVC-COV1901+boost MVC-COV1901	28	Adults including healthy or stable co-morbidities	1,125 (19)	868 (18)	1.29 [0.82, 2.02]	Plaque reduction neutralization test
Lien C, 2022 b	Protein subunit	MVC-COV1901	Boost MVC-COV1901+boost MVC-COV1901-Beta 25 mcg	Boost MVC-COV1901+boost MVC-COV1901	28	Adults including healthy or stable co-morbidities	929 (18)	868 (18)	1.06 [0.68, 1.67]	Plaque reduction neutralization test
Lien C, 2022 a	Protein subunit	MVC-COV1901	Boost MVC-COV1901-Beta 15 mcg	Boost MVC-COV1901	28	Adults including healthy or stable co-morbidities	1,805 (12)	1,352 (14)	1.33 [0.61, 2.89]	Plaque reduction neutralization test
Lien C, 2022 a	Protein subunit	MVC-COV1901	Boost MVC-COV1901-Beta 25 mcg	Boost MVC-COV1901	28	Adults including healthy or stable co-morbidities	3,603 (12)	1,352 (14)	2.64 [1.22, 5.79]	Plaque reduction neutralization test
Amplify, 2023 b	RNA based vaccine	BNT162b2	Boost Ad26.COV2.S 1*10^10 vp	Boost Ad26.COV2.S 5*10^10 vp	14	Adults including elderly and stable co-morbidities	3,218 (88)	4,439 (299)	0.725 [0.570, 0.922]	Virus neutralization assay (VNA)
Amplify, 2023 b	RNA based vaccine	BNT162b2	Boost Ad26.COV2.S 2.5*10^10 vp	Boost Ad26.COV2.S 5*10^10 vp	14	Adults including elderly and stable co-morbidities	3,566 (295)	4,439 (299)	0.803 [0.696, 0.927]	Virus neutralization assay (VNA)
Amplify, 2023 a	Non replicating viral vector	Ad26.COV2.S	Boost Ad26.COV2.S 1*10^10 vp	Boost Ad26.COV2.S 5*10^10 vp	14	Adults including elderly and stable co-morbidities	734 (93)	1,130 (298)	0.649 [0.484, 0.827]	Virus neutralization assay (VNA)
Amplify, 2023 a	Non replicating viral vector	Ad26.COV2.S	Boost Ad26.COV2.S 2.5*10^10 vp	Boost Ad26.COV2.S 5*10^10 vp	14	Adults including elderly and stable co-morbidities	915 (297)	1,130 (298)	0.810 [0.665, 0.986]	Virus neutralization assay (VNA)
Al Kaabi N, 2023	Inactivated virus	BBIBP-CorV	Boost NVSI-06-09	Boost BBIBP-CorV	14	Healthy adults	2,349 (255)	506 (249)	4.64 [3.93, 5.47]	Live-virus microneutralization assay
Niyomnaitham S, 2022	Inactivated virus	CoronaVac	Boost ChAdOx1 (1/5 dose ID)	Boost BNT162b2 (1/6 dose ID)	14	Healthy adults	206 (45)	288 (45)	0.71 [0.48, 1.07]	Plaque reduction neutralization test
Branche A, 2023	Any COVID-19 vaccine	BNT162b2 OR mRNA-1273 OR Ad26.COV2.S	2nd Boost BNT162b2 Omicron BA.1	2nd Boost BNT162b2 Omicron BA.4/5	14	Adults including healthy or stable co-morbidities	27,000 (98)	34,109 (98)	0.79 [0.64, 0.97]	Pseudovirus Neutralization Assay
Rao C, 2022	Inactivated virus	CoronaVac	Boost SCB-2019	Boost CoronaVac	14	Adults who are healthy or have a stable pre-existing medical condition	744 (209)	164 (211)	4.63 [3.96, 5.41]	Microneutralization assay
Niyomnaitham S, 2023	Inactivated virus	Coronavac	Boost ChAdOx1	Boost BNT162b2	28	Healthy adults	575 (97)	928 (99)	NR	Micro Neutralizing Antibody Titer
Omma A, 2022	Inactivated virus	CoronaVac	Boost TURKOVAC	Boost CoronaVac	28	Adults	34 (104)	28 (114)	1.45 [0.36, 5.80]	Microneutralization test (MNT)
Launay O, 2022	RNA based vaccine	BNT162b2	Boost MV B1.351	Boost BNT162b2	15	Adults including healthy or stable co-morbidities	1,801 (71)	1,364 (76)	1.32 [0.95, 1.83]	Microneutralization test
Launay O, 2022	RNA based vaccine	BNT162b2	Boost MV D614	Boost BNT162b2	15	Adults including healthy or stable co-morbidities	1,168 (76)	1,364 (76)	0.86 [0.62, 1.18]	Microneutralization test
Li J, 2022	Inactivated virus	CoronaVac	Boost Ad5-vectored	Boost Coronavac	14	Healthy adults	197 (96)	34 (102)	5.9 [4.5, 7.7]	Cytopathic effect-based microneutralization assay- wild-type SARS-CoV-2
Cao Y, 2021	Inactivated virus	CoronaVac	Boost ZF2001	Boost CoronaVac	14	Healthcare workers	1,306 (81)	794 (40)	1.64 [1.09, 2.46]	CPE
Nanthapisal S, 2022	Inactivated virus	2 doses of CoronaVac 21-28 days apart	Boost ChAdOx1-S standard dose	Boost ChAdOx1-S low-dose	14	Healthy adults	96 (207)	97 (203)	0.99 [0.97, 1.01]	Virus neutralization test (sVNT)
Shinkai M, 2022	RNA based vaccine	BNT162b2	Boost S-268019-b	Boost BNT162b2	14	Adults	128 (101)	139 (101)	0.94 [0.76, 1.09]	Cytopathic effect-based virus neutralization test
Branche A, 2022 a	Any COVID-19 vaccine	Completed primary and booster COVID-19 vaccine series, either homologous or heterologous	Boost mRNA Omicron + Beta vaccine	Boost Original mRNA-1273 vaccine	15	Adults	19,760 (198)	20,969 (97)	0.94 [0.73, 1.22]	Pseudovirion-based neutralisation assay
Branche A, 2022 a	Any COVID-19 vaccine	Completed primary and booster COVID-19 vaccine series, either homologous or heterologous	Boost mRNA Omicron + Delta vaccine	Boost Original mRNA-1273 vaccine	15	Adults	24,337 (99)	20,969 (97)	1.16 [0.85, 1.59]	Pseudovirion-based neutralisation assay
Branche A, 2022 a	Any COVID-19 vaccine	Completed primary and booster COVID-19 vaccine series, either homologous or heterologous	Boost mRNA Omicron + Original mRNA-1273 vaccine	Boost Original mRNA-1273 vaccine	15	Adults	26,125 (96)	20,969 (97)	1.25 [0.95, 1.64]	Pseudovirion-based neutralisation assay
Branche A, 2022 a	Any COVID-19 vaccine	Completed primary and booster COVID-19 vaccine series, either homologous or heterologous	Boost mRNA Omicron vaccine	Boost Original mRNA-1273 vaccine	15	Adults	19,167 (96)	20,969 (97)	0.91 [0.70, 1.20]	Pseudovirion-based neutralisation assay
Mok C K P, 2022	Inactivated virus	CoronaVac	Boost CoronaVac	Boost BNT162b2	30	Adults	17 (40)	207 (40)	NR	PRNT90
Toledo-Romani ME, 2022 a	Protein subunit	FINLAY-FR-2-25 mcg	Boost FR-1	Boost FINLAY-FR-2	28	Healthy adults	43 (55)	33 (51)	1.29 [0.81, 2.06]	Conventional virus neutralization test
Assantachai P, 2023	Non replicating viral vector	ChAdOx1	Boost mRNA-1273 20 mcg ID	Boost mRNA-1273	14-28	Adults	1,212 (35)	1,718 (35)	0.70 [0.40, 1.23]	Pseudovirus neutralization test assay
Assantachai P, 2023	Non replicating viral vector	ChAdOx1	Boost BNT162b2 10 mcg ID	Boost BNT162b2	14-28	Adults	587 (68)	713 (68)	0.82 [0.51, 1.31]	Pseudovirus neutralization test assay
He Q, 2022 b	Inactivated virus	CoronaVac or BBIBP-CorV	Boost BV-01-B5	Boost BV-01-B5	14	Healthy adults	1,327 (24)	1,327 (24)	2.06 [0.92, 4.59]	Pseudovirus neutralization assay
Barda N, 2023	RNA based vaccine	BNT162b2	Boost BNT161b2-OMI 30mcg	Boost BNT162b2	30	Adults	3,010 (18)	4,390 (20)	0.68 [0.32, 1.47]	Live Micro-neutralization assay
Barda N, 2023	RNA based vaccine	BNT162b2	Boost BNT161b2-OMI 60mcg	Boost BNT162b2	30	Adults	3,808 (19)	4,390 (20)	0.87 [0.42, 1.79]	Live Micro-neutralization assay
Barda N, 2023	RNA based vaccine	BNT162b2	Boost BNT161b2-OMI 15/15mcg	Boost BNT162b2	30	Adults	5,288 (19)	4,390 (20)	1.20 [0.63, 2.29]	Live Micro-neutralization assay
Barda N, 2023	RNA based vaccine	BNT162b2	Boost BNT161b2-OMI 30/30mcg	Boost BNT162b2	30	Adults	2,521 (20)	4,390 (20)	0.57 [0.28, 1.18]	Live Micro-neutralization assay
Barda N, 2023	RNA based vaccine	BNT162b2	Boost BNT162b2 60mcg	Boost BNT162b2	30	Adults	2,048 (18)	4,390 (20)	0.47 [0.21, 1.06]	Live Micro-neutralization assay
Corominas J, 2023	RNA based vaccine	BNT162b2	Boost PHH-1V	Boost BNT162b2	14	Healthy adults	1,966 (500)	3,309 (241)	0.59 [0.51, 0.69]	PNA
Winokur P, 2023	RNA based vaccine	BNT162b2	Boost biv BNT162b2 OMI 15/15mcg	Boost BNT162b2	30	Adults	6,945 (216)	7,377 (221)	0.94 [0.78, 1.04]	Recombinant SARS-CoV-2 neutralization assay
Winokur P, 2023	RNA based vaccine	BNT162b2	Boost BNT162b2 OMI 60mcg	Boost BNT162b2	30	Adults	8,447 (218)	7,377 (221)	1.14 [0.93, 1.40]	Recombinant SARS-CoV-2 neutralization assay
Winokur P, 2023	RNA based vaccine	BNT162b2	Boost biv BNT162b2 OMI 30/30mcg	Boost BNT162b2	30	Adults	9,355 (216)	7,377 (221)	1.27 [1.04, 1.54]	Recombinant SARS-CoV-2 neutralization assay
Winokur P, 2023	RNA based vaccine	BNT162b2	Boost BNT162b2 OMI 30mcg	Boost BNT162b2	30	Adults	6,815 (222)	7,377 (221)	0.92 [0.75, 1.13]	Recombinant SARS-CoV-2 neutralization assay
Winokur P, 2023	RNA based vaccine	BNT162b2	Boost BNT162b2 60mcg	Boost BNT162b2	30	Adults	8,244 (220)	7,377 (221)	1.11 [0.92, 1.34]	Recombinant SARS-CoV-2 neutralization assay
Jin L, 2022	Inactivated virus	CoronaVac	Boost Ad5-vectored high dose	Boost CoronaVac	28	Healthy adults	1,635 (40)	70 (40)	23.42 [19.05, 30.40]	CPE-based microneutralisation
Jin L, 2022	Inactivated virus	CoronaVac	Boost Ad5-vectored low dose	Boost CoronaVac	28	Healthy adults	1,911 (40)	70 (40)	27.40 [22.27, 35.39]	CPE-based microneutralisation
Wang L, 2022	Inactivated virus	CoronaVac	Boost CoronaVac 1.5 10m	Boost CoronaVax 1.5 12m	28	Children and adolescents	598 (85)	462 (85)	1.29 [0.89, 1.86]	Micro cytopathic effect assay
Wang L, 2022	Inactivated virus	CoronaVac	Boost CoronaVax 3 10m	Boost CoronaVax 3 12m	28	Children and adolescents	681 (85)	754 (82)	0.91 [0.64, 1.28]	Micro cytopathic effect assay
Sablerolles R, 2022	Non replicating viral vector	Ad26.COV2.S	Boost m-RNA-1273	Boost Ad26.COV2.S	28	Healthcare workers	5,686 (11)	614 (12)	9.26 [5.20, 16.48]	PRNT
Sablerolles R, 2022	Non replicating viral vector	Ad26.COV2.S	Boost BNT162b2	Boost Ad26.COV2.S	28	Healthcare workers	2,204 (12)	614 (12)	3.58 [1.11, 11.59]	PRNT
Tang R, 2023	Inactivated virus	Coronavac	Boost Coronovac/BoostAd5-nCoV IN	Boost Coronovac/boost Coronavac	14	Healthy adults	292 (117)	78 (116)	3.7 [2.6, 5.1]	Cytopathic effect-based microneutralization assay
Tang R, 2023	Inactivated virus	Coronavac	Boost Coronovac/Ad5-nCoV INCoV IM	Boost Coronovac/boost Coronavac	14	Healthy adults	746 (118)	78 (116)	9.5 [7.3, 12.3]	Cytopathic effect-based microneutralization assay
Estephan L, 2023 a	Protein subunit	MVC-COV1901	Boost 1/2 MVC-COV1901	Boost MVC-COV1901	28	Adults	985 (75)	1,690 (75)	0.58 [0.43, 0.79]	Live virus neutralization assay
Estephan L, 2023 a	Protein subunit	MVC-COV1901	Boost 1/2 mRNA-1273	Boost MVC-COV1901	28	Adults	5,934 (75)	1,690 (75)	3.51 [2.59, 4.76]	Live virus neutralization assay
Estephan L, 2023 a	Protein subunit	MVC-COV1901	Boost ChAdOx1	Boost MVC-COV1901	28	Adults	3,835 (77)	1,690 (75)	2.27 [1.67, 3.07]	Live virus neutralization assay
Estephan L, 2023 c	RNA based vaccine	mRNA-1273	Boost MVC-COV1901	Boost 1/2 mRNA-1273	28	Adults	735 (33)	2,635 (44)	0.28 [0.19, 0.40]	Live virus neutralization assay
Estephan L, 2023 c	RNA based vaccine	mRNA-1273	Boost ChAdOx1	Boost 1/2 mRNA-1273	28	Adults	1,632 (41)	2,635 (44)	0.62 [0.44, 0.87]	Live virus neutralization assay
Estephan L, 2023 c	RNA based vaccine	mRNA-1273	Boost 1/2 MVC-COV1901	Boost 1/2 mRNA-1273	28	Adults	577 (41)	2,635 (44)	0.22 [0.16, 0.31]	Live virus neutralization assay
Estephan L, 2023 b	Non replicating viral vector	ChadOx1	Boost MVC-COV1901	Boost ChadOx1	28	Adults	673 (75)	232 (79)	2.90 [2.22, 3.80]	Live virus neutralization assay
Estephan L, 2023 b	Non replicating viral vector	ChadOx1	Boost mRNA-1273 (half dose)	Boost ChadOx1	28	Adults	3,121 (75)	232 (79)	13.48 [10.30, 17.62]	Live virus neutralization assay
Leung N, 2022	RNA based vaccine	BNT162b2	Boost CoronaVac	Boost BNT162b2	28	Adults including co-morbidities	92 (20)	816 (20)	NR	Live virus plaque reduction neutralization test PRNT50
Leung N, 2022	Inactivated virus	CoronaVac	Boost BNT162b2	Boost CoronaVac	28	Adults including co-morbidities	905 (20)	109 (20)	NR	Live virus plaque reduction neutralization test PRNT50
He Q, 2022 a	Protein subunit	CoronaVac or BBIBP-CorV	Boost V-01D-351	Boost CoronaVac	14	Healthy adults	5,609 (11)	501 (9)	11.20 [6.49, 19.30]	Pseudovirus neutralization assay
Jin P, 2023 a	Inactivated virus	CoronaVac	Boost Ad5-vectored 5×10^10 vp	Boost CoronaVac	14	Elderly	286 (50)	48 (50)	5.94 [4.61, 7.65]	Microneutralization assay
Kulkarni P, 2023 a	Non replicating viral vector	ChAdOx1	Boost SII-NVX-CoV2373	Boost ChAdOx1	29	Adults	3,963 (92)	2,032 (93)	1.95 [1.52, 2.50]	Microneutralization assay (MN)
Toback S, 2023	Inactivated virus	BBIBP-CorV	Boost NVX-CoV2373	Boost BBIBP-CorV	14	Healthy volunteers	3,185 (479)	559 (486)	5.7 [5.1, 6.4]	Plaque Reduction Neutralization Test (PRNT)
Kulkarni P , 2023 b	Inactivated virus	BBV152	Boost SII-NVX-CoV2373	Boost BBV152	29	Adults	2,848 (91)	516 (93)	5.5 [4, 7.8]	Microneutralization assay (MN)

Geometric mean titre neutralization assay- omicron

Reference	Type of prime vaccination	Prime schedule	Intervention 1	Intervention 2	Follow up days	Participants	GMT Boost1 (N1)	GMT Boost2 (N2)	GMR [95% CI]	Evaluated by	Risk of bias
											A	B	C	D	E	Overall
Al Kaabi N, 2022 b	Inactivated virus	BBIBP-CorV	Boost NVSI-06-08 7-9 months	Boost BBIBP-CorV 7-9 months	15	Healthy adults	368 (270)	45 (270)	8.17 [6.03, 11.06]	Live-virus neutralization assay
Lien C, 2022 b	Protein subunit	MVC-COV1901	Boost MVC-COV1901+boost MVC-COV1901-Beta 15 mcg	Boost MVC-COV1901+boost MVC-COV1901	28	Adults including healthy or stable co-morbidities	222 (19)	137 (18)	1.62 [0.86, 3.05]	Pseudovirus neutralisation assay
Lien C, 2022 b	Protein subunit	MVC-COV1901	Boost MVC-COV1901+boost MVC-COV1901-Beta 25 mcg	Boost MVC-COV1901+boost MVC-COV1901	28	Adults including healthy or stable co-morbidities	155 (18)	137 (18)	1.13 [0.67, 1.89]	Pseudovirus neutralisation assay
Lien C, 2022 a	Protein subunit	MVC-COV1901	Boost MVC-COV1901-Beta 15 mcg	Boost MVC-COV1901	28	Adults including healthy or stable co-morbidities	240 (12)	139 (14)	1.72 [0.76, 3.91]	Pseudovirus neutralisation assay.
Lien C, 2022 a	Protein subunit	MVC-COV1901	Boost MVC-COV1901-Beta 25 mcg	Boost MVC-COV1901	28	Adults including healthy or stable co-morbidities	426 (12)	139 (14)	3.05 [1.44, 6.47]	Pseudovirus neutralisation assay.
Al Kaabi N, 2023	Inactivated virus	BBIBP-CorV	Boost NVSI-06-09	Boost BBIBP-CorV	14	Healthy adults	1,714 (255)	143 (249)	11.96 [9.60, 14.90]	Live-virus neutralizing antibody response against Omicron (BA.1.1) variant (PPS)
Niyomnaitham S, 2022	Inactivated virus	CoronaVac	Boost ChAdOx1 (1/5 dose ID)	Boost BNT162b2 (1/6 dose ID)	14	Healthy adults	46 (45)	53 (45)	0.87 [0.55, 1.38]	Plaque reduction neutralization test (PRNT50)
Branche A, 2023	Any COVID-19 vaccine	BNT162b2 OR mRNA-1273 OR Ad26.COV2.S	2nd Boost BNT162b2 Omicron BA.1	2nd Boost BNT162b2 Omicron BA.4/5	14	Adults including healthy or stable co-morbidities	3,546 (98)	5,939 (98)	0.60 [0.43, 0.83]	Pseudovirus neutralization assay
Rao C, 2022	Inactivated virus	CoronaVac	Boost SCB-2019	Boost CoronaVac	14	Adults who are healthy or have a stable pre-existing medical condition	253 (209)	73 (211)	3.45 [2.70, 4.42]	Microneutralization assay
Niyomnaitham S, 2023	Inactivated virus	Coronavac	Boost ChAdOx1	Boost BNT162b2	28	Healthy adults	119 (97)	256 (99)	0.46 [0.36, 0.59]	Pseudovirus Neutralizing Antibody Titers (PVNT50)
Launay O, 2022	RNA based vaccine	BNT162b2	Boost MV B1.351	Boost BNT162b2	15	Adults including healthy or stable co-morbidities	253 (71)	140 (76)	1.81 [1.34, 2.44]	Microneutralization test
Launay O, 2022	RNA based vaccine	BNT162b2	Boost MV D614	Boost BNT162b2	15	Adults including healthy or stable co-morbidities	124 (76)	140 (76)	0.88 [0.67, 1.17]	Microneutralization test
Costa Clemens SA, 2022	Inactivated virus	CoronaVac	Boost BNT162b2	Boost CoronaVac	28	Healthy adults	223 (20)	17 (20)	13.12 [5.66, 30.40]	Live-virus neutralization assay against Omicron
Costa Clemens SA, 2022	Inactivated virus	CoronaVac	Boost ChAdOx1	Boost CoronaVac	28	Healthy adults	102 (20)	17 (20)	6 [2.91, 12.36]	Live-virus neutralization assay against Omicron
Costa Clemens SA, 2022	Inactivated virus	CoronaVac	Boost AD26.COV2-S	Boost CoronaVac	28	Healthy adults	138 (20)	17 (20)	8.12 [3.72, 17.69]	Live-virus neutralization assay against Omicron
Branche A, 2022 a	Any COVID-19 vaccine	Completed primary and booster COVID-19 vaccine series, either homologous or heterologous	Boost mRNA Omicron + Beta vaccine	Boost Original mRNA-1273 vaccine	15	Adults	4,784 (198)	2,699 (97)	1.77 [1.24, 2.53]	Pseudotyped lentiviruses
Branche A, 2022 a	Any COVID-19 vaccine	Completed primary and booster COVID-19 vaccine series, either homologous or heterologous	Boost mRNA Omicron + Delta vaccine	Boost Original mRNA-1273 vaccine	15	Adults	4,503 (99)	2,699 (97)	1.67 [1.09, 2.54]	Pseudotyped lentiviruses
Branche A, 2022 a	Any COVID-19 vaccine	Completed primary and booster COVID-19 vaccine series, either homologous or heterologous	Boost mRNA Omicron + Original mRNA-1273 vaccine	Boost Original mRNA-1273 vaccine	15	Adults	5,322 (96)	2,699 (97)	1.97 [1.31, 2.95]	Pseudotyped lentiviruses
Branche A, 2022 a	Any COVID-19 vaccine	Completed primary and booster COVID-19 vaccine series, either homologous or heterologous	Boost mRNA Omicron vaccine	Boost Original mRNA-1273 vaccine	15	Adults	6,011 (96)	2,699 (97)	2.23 [1.52, 3.26]	Pseudotyped lentiviruses
Puthanakit T, 2022 b	Any COVID-19 vaccine	CoronaVac 3 mcg (0.5mL)/BNT162b2 30 mcg or BNT162b2 20 mcg	Boost BNT162b2 15mcg	Boost BNT162b2 30mcg		Adolescents	0 (*)	0 (*)	NR	NR
Puthanakit T, 2022 b	Any COVID-19 vaccine	CoronaVac 3 mcg (0.5mL)/BNT162b2 30 mcg or BNT162b2 20 mcg	Boost BNT162b2 10mcg	Boost BNT162b2 30mcg		Adolescents	0 (*)	0 (*)	NR	NR
Rose W, 2023	Non replicating viral vector	ChAdOx1	Boost BBV152	Boost ChAdOx1		Adults	0 (*)	0 (*)	NR	NR
Rose W, 2023	Inactivated virus	BBV152	Boost ChAdOx1	Boost BBV152		Adults	0 (*)	0 (*)	NR	NR
Assantachai P, 2023	Non replicating viral vector	ChAdOx1	Boost mRNA-1273 20 mcg ID	Boost mRNA-1273	14-28	Adults	318 (35)	617 (35)	0.51 [0.29, 0.92]	Pseudovirus neutralization test assay
Assantachai P, 2023	Non replicating viral vector	ChAdOx1	Boost BNT162b2 10 mcg ID	Boost BNT162b2	14-28	Adults	148 (68)	230 (68)	0.64 [0.42, 0.98]	Pseudovirus neutralization test assay
He Q, 2022 b	Inactivated virus	CoronaVac or BBIBP-CorV	Boost BV-01-B5	Boost BV-01-B5	14	Healthy adults	500 (24)	500 (24)	3.68 [1.15, 11.77]	Pseudovirus neutralization assay
Barda N, 2023	RNA based vaccine	BNT162b2	Boost BNT161b2-OMI 30mcg	Boost BNT162b2	30	Adults	575 (18)	402 (20)	1.43 [0.67, 3.06]	Live Micro-neutralization assay
Barda N, 2023	RNA based vaccine	BNT162b2	Boost BNT161b2-OMI 60mcg	Boost BNT162b2	30	Adults	765 (19)	402 (20)	1.90 [0.82, 4.44]	Live Micro-neutralization assay
Barda N, 2023	RNA based vaccine	BNT162b2	Boost BNT161b2-OMI 15/15mcg	Boost BNT162b2	30	Adults	1,062 (19)	402 (20)	2.64 [1.07, 6.53]	Live Micro-neutralization assay
Barda N, 2023	RNA based vaccine	BNT162b2	Boost BNT161b2-OMI 30/30mcg	Boost BNT162b2	30	Adults	478 (20)	402 (20)	1.19 [0.50, 2.87]	Live Micro-neutralization assay
Barda N, 2023	RNA based vaccine	BNT162b2	Boost BNT162b2 60mcg	Boost BNT162b2	30	Adults	188 (18)	402 (20)	0.47 [1.19, 1.17]	Live Micro-neutralization assay
Corominas J, 2023	RNA based vaccine	BNT162b2	Boost PHH-1V	Boost BNT162b2	14	Healthy adults	2,036 (500)	1,211 (241)	1.70 [1.41, 2]	Pseudovirion-based neutralisation assay (PBNA)
Winokur P, 2023	RNA based vaccine	BNT162b2	Boost biv BNT162b2 OMI 15/15mcg	Boost BNT162b2	30	Adults	884 (216)	663 (221)	1.33 [0.99, 1.78]	Recombinant SARS-CoV-2 neutralization assay
Winokur P, 2023	RNA based vaccine	BNT162b2	Boost BNT162b2 OMI 60mcg	Boost BNT162b2	30	Adults	1,836 (218)	663 (221)	2.76 [2.08, 3.67]	Recombinant SARS-CoV-2 neutralization assay
Winokur P, 2023	RNA based vaccine	BNT162b2	Boost biv BNT162b2 OMI 30/30mcg	Boost BNT162b2	30	Adults	1,140 (216)	663 (221)	1.71 [1.27, 2.32]	Recombinant SARS-CoV-2 neutralization assay
Winokur P, 2023	RNA based vaccine	BNT162b2	Boost BNT162b2 OMI 30mcg	Boost BNT162b2	30	Adults	1,346 (222)	663 (221)	2.03 [1.51, 2.72]	Recombinant SARS-CoV-2 neutralization assay
Winokur P, 2023	RNA based vaccine	BNT162b2	Boost BNT162b2 60mcg	Boost BNT162b2	30	Adults	821 (220)	663 (221)	1.23 [0.92, 1.65]	Recombinant SARS-CoV-2 neutralization assay
Jin L, 2022	Inactivated virus	CoronaVac	Boost Ad5-vectored high dose	Boost CoronaVac	28	Healthy adults	23 (40)	4 (40)	5.67 [3.01, 47.85]	Cyto-pathic effect-based microneutralization assay
Jin L, 2022	Inactivated virus	CoronaVac	Boost Ad5-vectored low dose	Boost CoronaVac	28	Healthy adults	52 (40)	4 (40)	12.77 [6.61, 188.68]	Cyto-pathic effect-based microneutralization assay
Wang L, 2022	Inactivated virus	CoronaVac	Boost CoronaVac 1.5 10m	Boost CoronaVax 1.5 12m	28	Children and adolescents	24 (85)	24 (85)	0.93 [0.65, 1.47]	micro cytopathogenic effect assay
Wang L, 2022	Inactivated virus	CoronaVac	Boost CoronaVax 3 10m	Boost CoronaVax 3 12m	28	Children and adolescents	35 (85)	40 (82)	0.86 [0.60, 1.23]	micro cytopathogenic effect assay
Chuang C-H, 2022	Non replicating viral vector	ChAdOx1	Boost BNT162b2	Boost MVC-COV1901	28	Healthcare workers	146 (30)	37 (30)	NR	Live virus neutralization
Chuang C-H, 2022	Non replicating viral vector	ChAdOx1	Boost mRNA-1273 (half dose)	Boost MVC-COV1901	28	Healthcare workers	204 (30)	37 (30)	5.51 [3.42, 8.90]	Live virus neutralization
Chuang C-H, 2022	Non replicating viral vector	ChAdOx1	Boost mRNA-1273	Boost MVC-COV1901	28	Healthcare workers	250 (30)	37 (30)	6.75 [4.30, 10.61]	Live virus neutralization
Tang R, 2023	Inactivated virus	Coronavac	Boost Coronovac/BoostAd5-nCoV IN	Boost Coronovac/boost Coronavac	14	Healthy adults	63 (117)	21 (116)	3.0 [2.3, 3.8]	Pseudovirus neutralisation tests
Tang R, 2023	Inactivated virus	Coronavac	Boost Coronovac/Ad5-nCoV INCoV IM	Boost Coronovac/boost Coronavac	14	Healthy adults	117 (118)	21 (116)	5.6 [4.6, 7.3]	Pseudovirus neutralisation tests
Estephan L, 2023 a	Protein subunit	MVC-COV1901	Boost 1/2 MVC-COV1901	Boost MVC-COV1901	28	Adults	195 (75)	247 (75)	NR	Pseudovirus neutralizing assay
Estephan L, 2023 a	Protein subunit	MVC-COV1901	Boost 1/2 mRNA-1273	Boost MVC-COV1901	28	Adults	955 (75)	247 (75)	NR	Pseudovirus neutralizing assay
Estephan L, 2023 a	Protein subunit	MVC-COV1901	Boost ChAdOx1	Boost MVC-COV1901	28	Adults	661 (77)	247 (75)	NR	Pseudovirus neutralizing assay
Estephan L, 2023 c	RNA based vaccine	mRNA-1273	Boost MVC-COV1901	Boost 1/2 mRNA-1273	28	Adults	105 (33)	658 (44)	NR	Pseudovirus neutralizing assay
Estephan L, 2023 c	RNA based vaccine	mRNA-1273	Boost ChAdOx1	Boost 1/2 mRNA-1273	28	Adults	657 (41)	658 (44)	NR	Pseudovirus neutralizing assay
Estephan L, 2023 c	RNA based vaccine	mRNA-1273	Boost 1/2 MVC-COV1901	Boost 1/2 mRNA-1273	28	Adults	68 (41)	658 (44)	NR	Pseudovirus neutralizing assay
Estephan L, 2023 b	Non replicating viral vector	ChadOx1	Boost MVC-COV1901	Boost ChadOx1	28	Adults	63 (75)	27 (79)	NR	Pseudovirus neutralizing assay
Estephan L, 2023 b	Non replicating viral vector	ChadOx1	Boost mRNA-1273 (half dose)	Boost ChadOx1	28	Adults	651 (75)	27 (79)	NR	Pseudovirus neutralizing assay
Leung N, 2022	RNA based vaccine	BNT162b2	Boost CoronaVac	Boost BNT162b2	28	Adults including co-morbidities	6 (20)	67 (20)	NR	Live virus plaque reduction neutralization test PRNT50
Leung N, 2022	Inactivated virus	CoronaVac	Boost BNT162b2	Boost CoronaVac	28	Adults including co-morbidities	80 (20)	6 (20)	NR	Live virus plaque reduction neutralization test PRNT50
He Q, 2022 a	Protein subunit	CoronaVac or BBIBP-CorV	Boost V-01D-351	Boost CoronaVac	14	Healthy adults	192 (11)	16 (9)	12 [3.33, 43.19]	Pseudovirus neutralization assay
Jin P, 2023 a	Inactivated virus	CoronaVac	Boost Ad5-vectored 5×10^10 vp	Boost CoronaVac	14	Elderly	33 (50)	4 (50)	7.5 [4.7, 11.9]	Microneutralization assay
Kulkarni P, 2023 a	Non replicating viral vector	ChAdOx1	Boost SII-NVX-CoV2373	Boost ChAdOx1	29	Adults	165 (92)	87 (93)	1.89 [1.04, 3.45]	Microneutralization assay (MN)
Kulkarni P , 2023 b	Inactivated virus	BBV152	Boost SII-NVX-CoV2373	Boost BBV152	29	Adults	194 (91)	41 (93)	4.72 [2.54, 8.77]	Microneutralization assay (MN)
Li X, 2023	Inactivated virus	Any inactivated COVID-19 vaccine	Boost aerosolized Ad5-nCoV	Boost CoronaVac		Healthy volunteers	91 (*)	19 (*)	4.78 [3.84, 5.96]	Pseudovirus neutralization test

Safety
Serious adverse events

Reference	Type of prime vaccination	Prime schedule	Intervention 1	Intervention 2	Follow up months	Participants	r1/N1	r2/N2	RR [95% CI]	Risk of bias
										A	B	C	D	E	Overall
Anderson E, 2022	RNA based vaccine	mRNA-1273	Boost 50 mcg mRNA-1273.351	Boost 25 mcg mRNA-1273.351 and 25 mcg mRNA-1273	1	Healthy volunteers	0 / 25	1 / 23	0.31 [0.01 - 7.16]
Anderson E, 2022	RNA based vaccine	mRNA-1273	Boost 100 mcg mRNA-1273	Boost 25 mcg mRNA-1273.351 and 25 mcg mRNA-1273	1	Healthy volunteers	0 / 48	1 / 23	0.16 [0.01 - 3.81]
Lien C, 2022 b	Protein subunit	MVC-COV1901	Boost MVC-COV1901+boost MVC-COV1901-Beta 15 mcg	Boost MVC-COV1901+boost MVC-COV1901	0.9	Adults including healthy or stable co-morbidities	0 / 21	0 / 21	NR
Lien C, 2022 b	Protein subunit	MVC-COV1901	Boost MVC-COV1901+boost MVC-COV1901-Beta 25 mcg	Boost MVC-COV1901+boost MVC-COV1901	0.9	Adults including healthy or stable co-morbidities	0 / 20	0 / 21	NR
Lien C, 2022 a	Protein subunit	MVC-COV1901	Boost MVC-COV1901-Beta 15 mcg	Boost MVC-COV1901	0.9	Adults including healthy or stable co-morbidities	0 / 15	0 / 15	NR
Lien C, 2022 a	Protein subunit	MVC-COV1901	Boost MVC-COV1901-Beta 25 mcg	Boost MVC-COV1901	0.9	Adults including healthy or stable co-morbidities	0 / 15	0 / 15	NR
Amplify, 2023 b	RNA based vaccine	BNT162b2	Boost Ad26.COV2.S 1*10^10 vp	Boost Ad26.COV2.S 5*10^10 vp	4.5	Adults including elderly and stable co-morbidities	1 / 106	3 / 326	1.03 [0.11 - 9.75]
Amplify, 2023 b	RNA based vaccine	BNT162b2	Boost Ad26.COV2.S 2.5*10^10 vp	Boost Ad26.COV2.S 5*10^10 vp	4.5	Adults including elderly and stable co-morbidities	1 / 326	3 / 326	0.33 [0.03 - 3.19]
Amplify, 2023 a	Non replicating viral vector	Ad26.COV2.S	Boost Ad26.COV2.S 1*10^10 vp	Boost Ad26.COV2.S 5*10^10 vp	4.5	Adults including elderly and stable co-morbidities	0 / 116	1 / 330	0.95 [0.04 - 23.05]
Amplify, 2023 a	Non replicating viral vector	Ad26.COV2.S	Boost Ad26.COV2.S 2.5*10^10 vp	Boost Ad26.COV2.S 5*10^10 vp	4.5	Adults including elderly and stable co-morbidities	3 / 328	1 / 330	3.02 [0.32 - 28.87]
Fadlyana E, 2023	Inactivated virus	CoronaVac	boost BNT162b2	boost CoronaVac	28	Healthy adults	1 / 193	0 / 191	2.97 [0.12 - 72.43]
Fadlyana E, 2023	Inactivated virus	CoronaVac	boost BNT162b2	boost BNT162b2	28	Healthy adults	1 / 193	1 / 193	1 [0.06 - 15.87]
Fadlyana E, 2023	Inactivated virus	CoronaVac	boost BNT162b2 (half dose)	boost CoronaVac	28	Healthy adults	0 / 186	0 / 191	NR
Fadlyana E, 2023	Inactivated virus	CoronaVac	boost ChAdOx1 (half dose)	boost CoronaVac	28	Healthy adults	1 / 192	0 / 191	2.98 [0.12 - 72.8]
Al Kaabi N, 2023	Inactivated virus	BBIBP-CorV	Boost NVSI-06-09	Boost BBIBP-CorV	1	Healthy adults	0 / 260	0 / 256	NR
Lee I, 2023 a	Any COVID-19 vaccine	Any authorized COVID	Boost mRNA-1273.529	Boost mRNA-1273	1	Aged at least 16 years including healthy, elderly and/or stable co-morbidities	5 / 367	1 / 357	4.86 [0.57 - 41.43]
Lee l, 2023 b	Any COVID-19 vaccine	Any authorized COVID-19 vaccine of: BNT162b2, mRNA-1273, ChAdOx1, Ad26.COV2.S	Boost mRNA-1273.214	Boost mRNA-1273	1	Aged at least 16 years including healthy, elderly and/or stable co-morbidities	6 / 1422	5 / 1402	1.18 [0.36 - 3.87]
Branche A, 2023	Any COVID-19 vaccine	BNT162b2 OR mRNA-1273 OR Ad26.COV2.S	2nd Boost BNT162b2 Omicron BA.1	2nd Boost BNT162b2 Omicron BA.4/5	29	Adults including healthy or stable co-morbidities	0 / 101	0 / 101	NR
Rao C, 2022	Inactivated virus	CoronaVac	Boost SCB-2019	Boost CoronaVac	2.0	Adults who are healthy or have a stable pre-existing medical condition	0 / 214	1 / 216	0.34 [0.01 - 8.21]
Niyomnaitham S, 2023	Inactivated virus	Coronavac	Boost ChAdOx1	Boost BNT162b2	3	Healthy adults	0 / 307	0 / 308	NR
Tawinprai K, 2022	Inactivated virus	CoronaVac	Boost ChAdOx1	Boost BBIBP-CorV	0.5	Adults without active underlying disease	0 / 41	0 / 40	NR
Omma A, 2022	Inactivated virus	CoronaVac	Boost TURKOVAC	Boost CoronaVac	1	Adults	0 / 108	1 / 114	0.35 [0.01 - 8.54]
Launay O, 2022	RNA based vaccine	BNT162b2	Boost MV B1.351	Boost BNT162b2	0.5	Adults including healthy or stable co-morbidities	1 / 80	0 / 82	3.07 [0.13 - 74.36]
Launay O, 2022	RNA based vaccine	BNT162b2	Boost MV D614	Boost BNT162b2	0.5	Adults including healthy or stable co-morbidities	1 / 85	0 / 82	2.89 [0.12 - 70.04]
Poh XY, 2022	RNA based vaccine	BNT162b2	Boost mRNA-1273	Boost BNT162b2	28	Adults	0 / 48	0 / 50	NR
Li J, 2022	Inactivated virus	CoronaVac	Boost Ad5-vectored	Boost Coronavac	1	Healthy adults	0 / 96	0 / 102	NR
Reindl-Schwaighofer R, 2021	RNA based vaccine	BNT162b2 or mRNA-1273	Boost BNT162b2 or mRNA-1273	Boost Ad26COVS1	1	Kidney transplant recipients	2 / 99	3 / 99	0.67 [0.11 - 3.9]
Costa Clemens SA, 2022	Inactivated virus	CoronaVac	Boost BNT162b2	Boost CoronaVac	1	Healthy adults	1 / 339	0 / 291	2.58 [0.11 - 62.99]
Costa Clemens SA, 2022	Inactivated virus	CoronaVac	Boost ChAdOx1	Boost CoronaVac	1	Healthy adults	1 / 304	0 / 291	2.87 [0.12 - 70.22]
Costa Clemens SA, 2022	Inactivated virus	CoronaVac	Boost AD26.COV2-S	Boost CoronaVac	1	Healthy adults	3 / 305	0 / 291	6.68 [0.35 - 128.75]
Shinkai M, 2022	RNA based vaccine	BNT162b2	Boost S-268019-b	Boost BNT162b2	NR	Adults	0 / 101	0 / 103	NR
Bruminhent J, 2022	Inactivated virus	2 doses of CoronaVac (3–5 weeks apart) or followed by 1 dose of ChAdOx1 or 2 doses of ChAdOx1	CoronaVac or ChAdOx1/Boost BNT162b2 or mRNA-1273	Boost ChAdOx1	0.2	Kidney transplant recipients	0 / 40	0 / 37	NR
Rose W, 2023	Non replicating viral vector	ChAdOx1	Boost BBV152	Boost ChAdOx1	3	Adults	0 / 99	2 / 101	0.2 [0.01 - 4.2]
Rose W, 2023	Inactivated virus	BBV152	Boost ChAdOx1	Boost BBV152	3	Adults	1 / 102	1 / 102	1 [0.06 - 15.77]
Assantachai P, 2023	Non replicating viral vector	ChAdOx1	Boost mRNA-1273 20 mcg ID	Boost mRNA-1273	3	Adults	0 / 35	0 / 35	NR
Assantachai P, 2023	Non replicating viral vector	ChAdOx1	Boost BNT162b2 10 mcg ID	Boost BNT162b2	3	Adults	0 / 70	0 / 70	NR
He Q, 2022 b	Inactivated virus	CoronaVac or BBIBP-CorV	Boost BV-01-B5	Boost BV-01-B5	1	Healthy adults	0 / 24	0 / 24	NR
Corominas J, 2023	RNA based vaccine	BNT162b2	Boost PHH-1V	Boost BNT162b2	3.2	Healthy adults	1 / 513	0 / 252	1.48 [0.06 - 36.09]
Winokur P, 2023	RNA based vaccine	BNT162b2	Boost biv BNT162b2 OMI 15/15mcg	Boost BNT162b2	1.7	Adults	1 / 305	2 / 305	0.5 [0.05 - 5.49]
Winokur P, 2023	RNA based vaccine	BNT162b2	Boost BNT162b2 OMI 60mcg	Boost BNT162b2	1.7	Adults	0 / 306	2 / 305	0.2 [0.01 - 4.14]
Winokur P, 2023	RNA based vaccine	BNT162b2	Boost biv BNT162b2 OMI 30/30mcg	Boost BNT162b2	1.7	Adults	2 / 316	2 / 305	0.97 [0.14 - 6.81]
Winokur P, 2023	RNA based vaccine	BNT162b2	Boost BNT162b2 OMI 30mcg	Boost BNT162b2	1.7	Adults	3 / 307	2 / 305	1.49 [0.25 - 8.86]
Winokur P, 2023	RNA based vaccine	BNT162b2	Boost BNT162b2 60mcg	Boost BNT162b2	1.7	Adults	0 / 302	2 / 305	0.2 [0.01 - 4.19]
Jin L, 2022	Inactivated virus	CoronaVac	Boost Ad5-vectored high dose	Boost CoronaVac	12	Healthy adults	1 / 137	1 / 137	1 [0.06 - 15.83]
Jin L, 2022	Inactivated virus	CoronaVac	Boost Ad5-vectored low dose	Boost CoronaVac	6	Healthy adults	2 / 139	1 / 137	1.97 [0.18 - 21.49]
Kho M, 2022	RNA based vaccine	mRNA-1273 or BNT162b2	Boost mRNA-1273 (2 doses)	Boost mRNA-1273	0.9	Adult kidney transplant recipients	0 / 75	3 / 71	0.14 [0.01 - 2.57]
Kho M, 2022	RNA based vaccine	mRNA-1273 or BNT162b2	Boost Ad26.COV2-S	Boost mRNA-1273	0.9	Adult kidney transplant recipients	1 / 78	3 / 71	0.3 [0.03 - 2.85]
Wang L, 2022	Inactivated virus	CoronaVac	Boost CoronaVac 1.5 10m	Boost CoronaVax 1.5 12m	1	Children and adolescents	1 / 86	0 / 87	3.03 [0.13 - 73.46]
Wang L, 2022	Inactivated virus	CoronaVac	Boost CoronaVax 3 10m	Boost CoronaVax 3 12m	1	Children and adolescents	0 / 85	0 / 88	NR
Munro APS, 2022	RNA based vaccine	BNT162b2 + boost BNT162b2	Boost BNT162b2	Boost half dose m-RNA 1273	1.7	Healthy adults	1 / 39	0 / 39	3 [0.13 - 71.37]
Munro APS, 2022	Non replicating viral vector	ChadOx1 + boost BNT162b2	Boost BNT162b2	Boost half dose m-RNA 1273	1.7	Healthy adults	2 / 44	0 / 44	5 [0.25 - 101.12]
Sablerolles R, 2022	Non replicating viral vector	Ad26.COV2.S	Boost m-RNA-1273	Boost Ad26.COV2.S	1	Healthcare workers	0 / 112	0 / 106	NR
Sablerolles R, 2022	Non replicating viral vector	Ad26.COV2.S	Boost BNT162b2	Boost Ad26.COV2.S	1	Healthcare workers	0 / 111	0 / 106	NR
Costa Clemens, 2022	Non replicating viral vector	ChadOx1	Boost 9 mcg SCB-2019 + alum	Boost ChadOx1	0.92	Adults	0 / 30	0 / 29	NR
Costa Clemens, 2022	Non replicating viral vector	ChadOx1	Boost 9 mcg SCB-2019 + CpG + alum	Boost ChadOx1	0.92	Adults	1 / 29	0 / 29	3 [0.13 - 70.59]
Costa Clemens, 2022	Non replicating viral vector	ChadOx1	Boost 30 mcg SCB-2019 + CpG + alum	Boost ChadOx1	0.92	Adults	0 / 32	0 / 29	NR
Tang R, 2023	Inactivated virus	Coronavac	Boost Coronovac/BoostAd5-nCoV IN	Boost Coronovac/boost Coronavac	0.9	Healthy adults	0 / 117	0 / 119	NR
Tang R, 2023	Inactivated virus	Coronavac	Boost Coronovac/Ad5-nCoV INCoV IM	Boost Coronovac/boost Coronavac	0.9	Healthy adults	0 / 120	0 / 119	NR
Natori Y, 2023	RNA based vaccine	BNT162b2	Boost Ad26.COV2.S	Boost BNT162b2	1	Transplant recipients	0 / 28	0 / 30	NR
He Q, 2022 a	Protein subunit	CoronaVac or BBIBP-CorV	Boost V-01D-351	Boost CoronaVac	0.9	Healthy adults	0 / 11	0 / 9	NR
Jin P, 2023 a	Inactivated virus	CoronaVac	Boost Ad5-vectored 5×10^10 vp	Boost CoronaVac	6	Elderly	1 / 99	0 / 100	3.03 [0.12 - 73.49]
Intapiboon P, 2021	Inactivated virus	CoronaVac	CoronaVac 3mcg D0/14	CoronaVac	1	Healthy adults	0 / 30	0 / 30	NR
Intapiboon P, 2021	Inactivated virus	CoronaVac	CoronaVac 3mcg D0/14	CoronaVac	1	Healthy adults	0 / 31	0 / 30	NR
Akahata W, 2023 a	RNA based vaccine	BNT162b2	Boost VLPCOV-01 0.3 mcg	Boost BNT162b2	6	Healthy volunteers	0 / 10	0 / 10	NR
Akahata W, 2023 a	RNA based vaccine	BNT162b2	Boost VLPCOV-01 1 mcg	Boost BNT162b2	6	Healthy volunteers	0 / 10	0 / 10	NR
Akahata W, 2023 a	RNA based vaccine	BNT162b2	Boost VLPCOV-01 3 mcg	Boost BNT162b2	6	Healthy volunteers	0 / 10	0 / 10	NR
Akahata W , 2023 b	RNA based vaccine	BNT162b2	Boost VLPCOV-01 0.3 mcg	Boost BNT162b2	6	Healthy volunteers	0 / 10	0 / 10	NR
Akahata W , 2023 b	RNA based vaccine	BNT162b2	Boost VLPCOV-01 1 mcg	Boost BNT162b2	6	Healthy volunteers	0 / 10	0 / 10	NR
Akahata W , 2023 b	RNA based vaccine	BNT162b2	Boost VLPCOV-01 3 mcg	Boost BNT162b2	6	Healthy volunteers	0 / 10	0 / 10	NR
Toback S, 2023	Inactivated virus	BBIBP-CorV	Boost NVX-CoV2373	Boost BBIBP-CorV	1	Healthy volunteers	0 / 497	0 / 501	NR

r1: Number of events in intervention 1, r2: Number of events in intervention 2, N1: Number of patients analyzed in intervention 1; N2: Number of patients analyzed in intervention 2.

All-cause mortality

Reference	Type of prime vaccination	Prime schedule	Intervention 1	Intervention 2	Follow up months	Participants	r1/N1	r2/N2	RR [95% CI]	Risk of bias
										A	B	C	D	E	Overall
Al Kaabi N, 2022 b	Inactivated virus	BBIBP-CorV	Boost NVSI-06-08 4-6 months	Boost BBIBP-CorV 4-6 months	1	Healthy adults	0 / 299	0 / 301	NR
Al Kaabi N, 2022 b	Inactivated virus	BBIBP-CorV	Boost NVSI-06-08 7-9 months	Boost BBIBP-CorV 7-9 months	1	Healthy adults	0 / 297	0 / 303	NR
Al Kaabi N, 2022 b	Inactivated virus	BBIBP-CorV	Boost NVSI-06-08 >9 months	Boost BBIBP-CorV >9 months	1	Healthy adults	0 / 300	0 / 300	NR
Lien C, 2022 b	Protein subunit	MVC-COV1901	Boost MVC-COV1901+boost MVC-COV1901-Beta 15 mcg	Boost MVC-COV1901+boost MVC-COV1901	0.9	Adults including healthy or stable co-morbidities	0 / 21	0 / 21	NR
Lien C, 2022 b	Protein subunit	MVC-COV1901	Boost MVC-COV1901+boost MVC-COV1901-Beta 25 mcg	Boost MVC-COV1901+boost MVC-COV1901	0.9	Adults including healthy or stable co-morbidities	0 / 20	0 / 21	NR
Lien C, 2022 a	Protein subunit	MVC-COV1901	Boost MVC-COV1901-Beta 15 mcg	Boost MVC-COV1901	0.9	Adults including healthy or stable co-morbidities	0 / 15	0 / 15	NR
Lien C, 2022 a	Protein subunit	MVC-COV1901	Boost MVC-COV1901-Beta 25 mcg	Boost MVC-COV1901	0.9	Adults including healthy or stable co-morbidities	0 / 15	0 / 15	NR
Amplify, 2023 b	RNA based vaccine	BNT162b2	Boost Ad26.COV2.S 1*10^10 vp	Boost Ad26.COV2.S 5*10^10 vp	4.5	Adults including elderly and stable co-morbidities	0 / 106	0 / 326	NR
Amplify, 2023 b	RNA based vaccine	BNT162b2	Boost Ad26.COV2.S 2.5*10^10 vp	Boost Ad26.COV2.S 5*10^10 vp	4.5	Adults including elderly and stable co-morbidities	0 / 326	0 / 326	NR
Amplify, 2023 a	Non replicating viral vector	Ad26.COV2.S	Boost Ad26.COV2.S 1*10^10 vp	Boost Ad26.COV2.S 5*10^10 vp	4.5	Adults including elderly and stable co-morbidities	0 / 116	0 / 330	NR
Amplify, 2023 a	Non replicating viral vector	Ad26.COV2.S	Boost Ad26.COV2.S 2.5*10^10 vp	Boost Ad26.COV2.S 5*10^10 vp	4.5	Adults including elderly and stable co-morbidities	0 / 328	0 / 330	NR
Mrak D, 2022	RNA based vaccine	mRNA-1273 or BNT162b2	Boost ChAdOx1	Boost homologous mRNA-1273 or BNT162b2	0.9	Immunosuppressed adults	0 / 22	0 / 24	NR
Lee I, 2023 a	Any COVID-19 vaccine	Any authorized COVID	Boost mRNA-1273.529	Boost mRNA-1273	4.6	Aged at least 16 years including healthy, elderly and/or stable co-morbidities	0 / 367	0 / 357	NR
Lee l, 2023 b	Any COVID-19 vaccine	Any authorized COVID-19 vaccine of: BNT162b2, mRNA-1273, ChAdOx1, Ad26.COV2.S	Boost mRNA-1273.214	Boost mRNA-1273	2.9	Aged at least 16 years including healthy, elderly and/or stable co-morbidities	0 / 1422	0 / 1402	NR
Rao C, 2022	Inactivated virus	CoronaVac	Boost SCB-2019	Boost CoronaVac	2.0	Adults who are healthy or have a stable pre-existing medical condition	0 / 214	0 / 216	NR
Tawinprai K, 2022	Inactivated virus	CoronaVac	Boost ChAdOx1	Boost BBIBP-CorV	0.5	Adults without active underlying disease	0 / 41	0 / 40	NR
Reindl-Schwaighofer R, 2021	RNA based vaccine	BNT162b2 or mRNA-1273	Boost BNT162b2 or mRNA-1273	Boost Ad26COVS1	3	Kidney transplant recipients	4 / 99	4 / 99	1 [0.26 - 3.88]
Shinkai M, 2022	RNA based vaccine	BNT162b2	Boost S-268019-b	Boost BNT162b2	*	Adults	0 / 101	0 / 103	NR
Toledo-Romani ME, 2022 a	Protein subunit	FINLAY-FR-2-25 mcg	Boost FR-1	Boost FINLAY-FR-2	1	Healthy adults	0 / 58	0 / 55	NR
Rose W, 2023	Non replicating viral vector	ChAdOx1	Boost BBV152	Boost ChAdOx1	3.0	Adults	0 / 99	0 / 101	NR
Rose W, 2023	Inactivated virus	BBV152	Boost ChAdOx1	Boost BBV152	3.0	Adults	0 / 102	0 / 102	NR
Corominas J, 2023	RNA based vaccine	BNT162b2	Boost PHH-1V	Boost BNT162b2	3.2	Healthy adults	0 / 513	0 / 252	NR
Winokur P, 2023	RNA based vaccine	BNT162b2	Boost biv BNT162b2 OMI 15/15mcg	Boost BNT162b2	1.7	Adults	0 / 305	0 / 305	NR
Winokur P, 2023	RNA based vaccine	BNT162b2	Boost BNT162b2 OMI 60mcg	Boost BNT162b2	1.7	Adults	0 / 306	0 / 305	NR
Winokur P, 2023	RNA based vaccine	BNT162b2	Boost biv BNT162b2 OMI 30/30mcg	Boost BNT162b2	1.7	Adults	0 / 316	0 / 305	NR
Winokur P, 2023	RNA based vaccine	BNT162b2	Boost BNT162b2 OMI 30mcg	Boost BNT162b2	1.7	Adults	0 / 307	0 / 305	NR
Winokur P, 2023	RNA based vaccine	BNT162b2	Boost BNT162b2 60mcg	Boost BNT162b2	1.7	Adults	0 / 302	0 / 305	NR
Chuang C-H, 2022	Non replicating viral vector	ChAdOx1	Boost BNT162b2	Boost MVC-COV1901	5.9	Healthcare workers	0 / 83	0 / 85	NR
Chuang C-H, 2022	Non replicating viral vector	ChAdOx1	Boost mRNA-1273 (half dose)	Boost MVC-COV1901	5.9	Healthcare workers	0 / 85	0 / 85	NR
Chuang C-H, 2022	Non replicating viral vector	ChAdOx1	Boost mRNA-1273	Boost MVC-COV1901	5.9	Healthcare workers	0 / 85	0 / 85	NR
Costa Clemens, 2022	Non replicating viral vector	ChadOx1	Boost 9 mcg SCB-2019 + alum	Boost ChadOx1	2.53	Adults	0 / 30	0 / 29	NR
Costa Clemens, 2022	Non replicating viral vector	ChadOx1	Boost 9 mcg SCB-2019 + CpG + alum	Boost ChadOx1	2.53	Adults	0 / 29	0 / 29	NR
Costa Clemens, 2022	Non replicating viral vector	ChadOx1	Boost 30 mcg SCB-2019 + CpG + alum	Boost ChadOx1	2.53	Adults	0 / 32	0 / 29	NR
Tang R, 2023	Inactivated virus	Coronavac	Boost Coronovac/BoostAd5-nCoV IN	Boost Coronovac/boost Coronavac	0.9	Healthy adults	0 / 117	0 / 119	NR
Tang R, 2023	Inactivated virus	Coronavac	Boost Coronovac/Ad5-nCoV INCoV IM	Boost Coronovac/boost Coronavac	0.9	Healthy adults	0 / 120	0 / 119	NR
Estephan L, 2023 a	Protein subunit	MVC-COV1901	Boost 1/2 MVC-COV1901	Boost MVC-COV1901	5.16	Adults	0 / 78	0 / 78	NR
Estephan L, 2023 a	Protein subunit	MVC-COV1901	Boost 1/2 mRNA-1273	Boost MVC-COV1901	5.16	Adults	0 / 77	0 / 78	NR
Estephan L, 2023 a	Protein subunit	MVC-COV1901	Boost ChAdOx1	Boost MVC-COV1901	5.16	Adults	0 / 80	0 / 78	NR
Estephan L, 2023 c	RNA based vaccine	mRNA-1273	Boost MVC-COV1901	Boost 1/2 mRNA-1273	5.16	Adults	0 / 35	0 / 44	NR
Estephan L, 2023 c	RNA based vaccine	mRNA-1273	Boost ChAdOx1	Boost 1/2 mRNA-1273	5.16	Adults	0 / 42	0 / 44	NR
Estephan L, 2023 c	RNA based vaccine	mRNA-1273	Boost 1/2 MVC-COV1901	Boost 1/2 mRNA-1273	5.16	Adults	0 / 42	0 / 44	NR
Estephan L, 2023 b	Non replicating viral vector	ChadOx1	Boost MVC-COV1901	Boost ChadOx1	5.16	Adults	0 / 79	0 / 81	NR
Estephan L, 2023 b	Non replicating viral vector	ChadOx1	Boost mRNA-1273 (half dose)	Boost ChadOx1	5.16	Adults	0 / 82	0 / 81	NR
Natori Y, 2023	RNA based vaccine	BNT162b2	Boost Ad26.COV2.S	Boost BNT162b2	6	Transplant recipients	0 / 28	0 / 30	NR

r1: Number of events in intervention 1, r2: Number of events in intervention 2, N1: Number of patients analyzed in intervention 1; N2: Number of patients analyzed in intervention 2.

COVID-19 PRIME VACCINATION: Last search date December 14, 2022.

Vaccine efficacy and safety for vaccine vs placebo / no vaccine (forest plots)

Vaccine efficacy and safety for vaccine vs vaccine (forest plots)

Vaccine efficacy, immunogenicity and safety of heterologous vs homologous vaccination (tables)

Reference	Intervention 1	Intervention 2	Follow up months	Participants	r1/N1	r2/N2	RR [95% CI]	Risk of bias
	A	B	C	D	E	Overall
Toledo-Romani ME, 2022 b	FINLAY-FR-2-25 mcg +FR-1-50 mcg	Placebo	*	Adults	0 / 13828	6 / 12486	100.0 [*, 100]

Efficacy
Severe or critical COVID-19 after complete vaccination
Confirmed symptomatic COVID-19 after complete vaccination

Reference	Intervention 1	Intervention 2	Follow up months	Participants	r1/N1	r2/N2	VE [95% CI]	Risk of bias
	A	B	C	D	E	Overall
Toledo-Romani ME, 2022 b	FINLAY-FR-2-25 mcg +FR-1-50 mcg	Placebo	*	Adults	NR	NR	92.0 [80.4, 96.7]

Immunogenicity
Geometric mean titre specific antibodies

Reference	Intervention 1	Intervention 2	Follow up days	Participants	GMT1(N1)	GMT2(N2)	GMR [95% CI]	Evaluated by	Risk of bias
									A	B	C	D	E	Overall
Janssen C, 2022	1 dose BNT162b2/1 dose mRNA-1273	2 doses BNT162b2	28	Adults	3,706 (96)	2,698 (94)	1.37 [1.10, 1.72]	ELISA
Janssen C, 2022	1 dose mRNA-1273 /1 dose BNT162b2	2 doses mRNA-1273	28	Adults	2,690 (103)	3,995 (97)	0.67 [0.55, 0.82]	ELISA
Puthanakit T, 2022 a	CoronaVac followed by BNT162b2 30 at 6week interva	CoronaVac followed by BNT162b2 30 at 3week interva	21	Adolescents	112 (20)	77 (20)	1.28 [1.09, 1.51]	ELISA
Puthanakit T, 2022 a	CoronaVac followed by BNT162b2 20 at 3week interva	CoronaVac followed by BNT162b2 30 at 3week interva	21	Adolescents	84 (17)	77 (20)	0.95 [0.80, 1.13]	ELISA
Puthanakit T, 2022 a	CoronaVac followed by BNT162b2 20 at 6week interva	CoronaVac followed by BNT162b2 30 at 3week interva	21	Adolescents	74 (19)	77 (20)	1.10 [0.94, 1.30]	ELISA
Chen C, 2022	1 dose ChAdOx1 / 1 dose MVC-COV1901	ChAdOx1	10	Healthy adults	8 (50)	5 (50)	1.5 [1.2, 1.9]	ELISA
Li J, 2022	1 dose CoronaVac / 1 dose Ad5-vectored	2 doses CoronaVac	14	Healthy adults	942 (51)	154 (50)	6.11 [3.90, 9.57]	ELISA

N1: Number of patients analyzed in intervention 1; N2: Number of patients analyzed in intervention 2; GMT1: Geometric mean titre for intervention 1; GMT2: Geometric mean titre for intervention 2

Geometric mean titre neutralizing antibodies

Reference	Intervention 1	Intervention 2	Follow up days	Participants	GMT1(N1)	GMT2(N2)	GMR [95% CI]	Evaluated by	Risk of bias
									A	B	C	D	E	Overall
Janssen C, 2022	1 dose BNT162b2/1 dose mRNA-1273	2 doses BNT162b2	28	Adults	523 (96)	396 (94)	1.31 [1.02, 1.69]	CPE (cytopathic effect)-based virus neutralization test (VNT)
Chen C, 2022	1 dose ChAdOx1 / 1 dose MVC-COV1901	ChAdOx1	10	Healthy adults	202 (50)	78 (50)	2.6 [1.7, 4.0]	Plaque reduction neutralization
Li J, 2022	1 dose CoronaVac / 1 dose Ad5-vectored	2 doses CoronaVac	14	Healthy adults	54 (51)	13 (50)	4.3 [2.5, 7.3]	CPE-based microneutralization assay-wild-type
Jin P, 2022 b	CoronaVac/Ad5-nCoV	CoronaVac	14	Elderly	71 (48)	9 (47)	7.62 [4.44, 13.1]	Microneutralization assay

N1: Number of patients analyzed in intervention 1; N2: Number of patients analyzed in intervention 2; GMT1: Geometric mean titre for intervention 1; GMT2: Geometric mean titre for intervention 2

Safety
Serious adverse events

Reference	Intervention 1	Intervention 2	Follow up months	Participants	r1/N1	r2/N2	RR [95% CI]	Risk of bias
								A	B	C	D	E	Overall
Macchia A, 2022	Gam-COVID-Vac rAd26-S	Gam-COVID-Vac rAd26-S/BBIBP-CorV	1	Adults	0 / 87	0 / 65	NR
Stuart A, 2021 a	1 dose ChAdOx1 followed by 1 dose NVX-CoV2373	2 doses ChAdOx1	NR	Older adults	1 / 179	3 / 180	0.34 [0.04 - 3.19]
Stuart A, 2021 a	1 dose ChAdOx1 followed by 1 dose mRNA-1273	2 doses ChAdOx1	NR	Older adults	3 / 181	3 / 180	0.99 [0.2 - 4.86]
Stuart A, 2021 b	1 dose BNT162b2 followed by 1 dose NVX-CoV2373	2 doses BNT162b2	NR	Older adults	3 / 180	2 / 175	1.46 [0.25 - 8.62]
Stuart A, 2021 b	1 dose BNT162b2 followed by 1 dose mRNA-1273	2 doses BNT162b2	NR	Older adults	3 / 177	2 / 175	1.48 [0.25 - 8.77]
Janssen C, 2022	1 dose BNT162b2/1 dose mRNA-1273	2 doses BNT162b2	0.9	Adults	0 / 102	0 / 101	NR
Janssen C, 2022	1 dose mRNA-1273 /1 dose BNT162b2	2 doses mRNA-1273	0.9	Adults	0 / 106	0 / 105	NR
Liu X, 2022	1 dose ChAdOx1/ 1 dose BNT162b2	2 doses ChAdOx1	8.3	Adults	2 / 114	1 / 115	2.02 [0.19 - 21.94]
Liu X, 2022	1 dose BNT162b2 /1 dose ChAdOx1	2 doses BNT162b2	8.3	Adults	2 / 115	1 / 119	2.07 [0.19 - 22.51]
Bánki Z, 2022	1 dose ChAdOx1/ 1 dose BNT162b2	ChAdOx1	1	Healthy adults	1 / 114	0 / 108	2.84 [0.12 - 69.03]
Chen C, 2022	1 dose ChAdOx1 / 1 dose MVC-COV1901	ChAdOx1	0.9	Healthy adults	0 / 50	0 / 50	NR
Li J, 2022	1 dose CoronaVac / 1 dose Ad5-vectored	2 doses CoronaVac	1	Healthy adults	0 / 51	0 / 50	NR
Jin P, 2022 b	CoronaVac/Ad5-nCoV	CoronaVac	6	Elderly	1 / 50	2 / 50	0.5 [0.05 - 5.33]
Niyomnaitham S, 2022 a	CoronaVac/ChAdOx1	BNT162b2	2.8	Adults	0 / 30	0 / 26	NR
Niyomnaitham S, 2022 a	CoronaVac/BNT162b2	BNT162b2	2.8	Adults	0 / 30	0 / 26	NR
Niyomnaitham S, 2022 a	ChAdOx1/CoronaVac	BNT162b2	2.8	Adults	0 / 29	0 / 26	NR
Niyomnaitham S, 2022 a	ChAdOx1/BNT162b2	BNT162b2	2.8	Adults	0 / 26	0 / 26	NR
Niyomnaitham S, 2022 a	BNT162b2/CoronaVac	BNT162b2	2.8	Adults	0 / 29	0 / 26	NR
Niyomnaitham S, 2022 a	BNT162b2+ChAdOx1	BNT162b2	2.8	Adults	0 / 30	0 / 26	NR
Toledo-Romani ME, 2022 b	FINLAY-FR-2-25 mcg +FR-1-50 mcg	Placebo	2.7	Adults	1 / 14677	3 / 14675	0.33 [0.03 - 3.2]

r1: Number of events in intervention 1, r2: Number of events in intervention 2, N1: Number of patients analyzed in intervention 1; N2: Number of patients analyzed in intervention 2.

All-cause mortality

Reference	Intervention 1	Intervention 2	Follow up months	Participants	r1/N1	r2/N2	RR [95% CI]
	A	B	C	D	E	Overall
Chen C, 2022	1 dose ChAdOx1 / 1 dose MVC-COV1901	ChAdOx1	0.9	Healthy adults	0 / 50	0 / 50	NR
Toledo-Romani ME, 2022 b	FINLAY-FR-2-25 mcg +FR-1-50 mcg	Placebo	5.4	Adults	11 / 13883	24 / 14303	0.47 [0.23 - 0.96]

Vaccine efficacy and safety against variants of concern (forest plots)

Trials reports under extraction

In addition to the below included trials, we have included and presently extracting 12 new vaccine randomized trials

Description of primary studies

In this table, we report the main characteristics of the COVID-19 vaccine candidates from RCTs identified, in addition to the overall risk of bias assessment.

For prime vaccination, early phase trials were extracted only when the dose has been selected. Results from phase 1-2 studies are included in forest plots for the chosen vaccine dose and schedule only. List of early phases included but not extracted are detailed on here .

Search studies

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Trial	Type	Comparisons		Design	Participants	Sample size	Overall risk of bias Highest assessment	Full description
		Intervention 1	Intervention 2
NCT04400838 ; ISRCTN University of Oxford/AstraZeneca Ramasamy MN, Lancet, 2020 Full text Commentary (20)32481-8/fulltext ; Commentary ; Commentary	Non replicating viral vector	Non replicating viral vector ChAdOx1 nCoV-19 vaccine - 2·2 × 10¹? vp x 2 doses on day 0/28	Non replicating viral vector ChAdOx1 nCoV-19 vaccine - 2·2 × 10¹? vp x 2 doses on day 0/28	RCT Phase 2/3	Healthy adults in two centres in the UK	N= NR	N/A	Full description
NCT04651790 Sinovac Research and Development Co., Ltd Abarca K, medRxiv, 2022 Full text Commentary Commentary Commentary	Inactivated virus	CoronaVac	Coronavac D0/28	RCT Phase 3	Healthy adults including health care workers with no history of confirmed symptomatic SARS CoV-2 infection at eight centres in Chile	N= 2302	Some concerns Details	Full description
jRCT2051210164 VLP Therapeutics Japan; Pfizer/BioNTech + Fosun Pharma Akahata W , SSRN, 2023 b Full text Full text Commentary Commentary	saRNA based vaccine	BNT162b2/Boost VLPCOV-01 0.3 mcg BNT162b2/Boost VLPCOV-01 1 mcg BNT162b2/Boost VLPCOV-01 3 mcg	BNT162b2/boostBNT	RCT Phase 1	Healthy adults, ≥65 years years of age, SARS-CoV-2 infection-free in a single centre in Japan.	N= 46	Some concerns Details	Full description
jRCT2051210164 VLP Therapeutics Japan; Pfizer/BioNTech + Fosun Pharma Akahata W, SSRN, 2023 a Full text Full text Commentary Commentary	saRNA based vaccine	BNT162b2/Boost VLPCOV-01 0.3 mcg BNT162b2/Boost VLPCOV-01 1 mcg BNT162b2/Boost VLPCOV-01 3 mcg	BNT162b2/boostBNT	RCT Phase 1	Healthy adults, 18 to 55 years of age, SARS-CoV-2 infection-free in a single centre in Japan.	N= 46	Some concerns Details	Full description
NCT04510207, ChiCTR2000034780 Sinopharm-Beijing Al Kaabi N, JAMA, 2021 Full text Commentary Commentary	Inactivated virus	BBIBP-CorV	Adjuvant	RCT Phase 3	Healthy adults free of known COVID-19 or HIV infection at 3 centres in United Arab Emirates and Bahrain	N= 40411	Some concerns Details	Full description
NCT04510207 Sinopharm Al Kaabi N, Vaccines, 2023 Full text Commentary	Inactivated virus	BBIBP-CorV/Boost BBIBP-CorV WIBP-CorV/Boost WIBP-CorV	Placebo/Boost placebo	RCT Phase 3	Healthy volunteers with no history of SARS-CoV-2 in a single center in United Arab Emirates	N= 9370	Some concerns Details	Full description
NCT04510207, ChiCTR2000034780 Sinopharm-Wuhan Al Kaabi N, JAMA, 2021 Full text Commentary Commentary	Inactivated virus	WIBP-CorV	Adjuvant	RCT Phase 3	Healthy adults free of known COVID-19 or HIV infection at 3 centres in United Arab Emirates and Bahrain	N= 40411	Some concerns Details	Full description
NCT05293548 National Vaccine and Serum Institute, China, Beijing Zhong Sheng Heng Pharmaceutical Technology, Lanzhou Institute of Biological Products; Sinopharm-Beijing Al Kaabi N, Signal Transduct Ther, 2023 Full text Commentary Commentary	Protein subunit	BBIBP-CorV/Boost NVSI-06-09	BBIBP-CorV/Boost BBIBP-CorV	RCT Phase 2	Healthy adults previously vaccinated with two or three doses of BBIBP-CorV at least 6 months prior to enrollment at a single center in United Arab Emirates	N= 516	Some concerns Details	Full description
NCT05069129 Sinopharm-Beijing/ National Vaccine and Serum Institute, China Al Kaabi N, Nat Commun, 2022 b Full text Commentary Commentary	Heterologous booster	BBIBP-CorV/boostNVSI-06-08 4-6m BBIBP-CorV/boostNVSI-06-08 7-9m BBIBP-CorV/boostNVSI-06-08 >9m	BBIBP-CorV/boostBBIBP-CorV 4-6 months BBIBP-CorV/boostBBIBP-CorV 7-9m BBIBP-CorV/boostBBIBP-CorV >9m	RCT Phase 2	Healthy adults that were HIV-negative and with no previous history of COVID-19 in a single centre in the United Arab Emirates.	N= 1833	Some concerns Details	Full description
NCT04649151 ModernaTX Ali K, N Engl J Med, 2021 Full text Commentary	RNA based vaccine	mRNA-1273	Placebo	RCT Phase 2-3	Healthy adolescents in 26 centers in the USA	N= 3732	Some concerns Details	Full description

Bennett C, medRxiv, 2023	Immunogenicity and safety of heterologous Omicron BA.1 and bivalent SARS-CoV-2 recombinant spike protein booster vaccines: a phase 3, randomized, clinical trial
Chaudhary A, Vaccine, 2023	Characterization of immune responses to two and three doses of the adenoviral vectored vaccine ChAdOx1 nCov-19 and the whole virion inactivated vaccine BBV152 in a mix-and-match study in India.
Costa Clemens SA, Hum Vaccin Immunother, 2023	Immunogenicity, safety and reactogenicity of heterologous (third dose) booster vaccination with a full or fractional dose of two different COVID-19 vaccines: A phase 4, single-blind, randomized controlled trial in adults
Gui,EBioMedicine, 2023	Safety and immunogenicity of a modified COVID-19 mRNA vaccine, SW-BIC-213, as a heterologous booster in healthy adults: an open-labeled, two-centered and multi-arm randomised, phase 1 trial
Hannawi S, Nat Commun, 2023	Safety and immunogenicity of a tetravalent and bivalent SARS-CoV-2 protein booster vaccine in men.
Huang T, The Lancet, 2023	Safety and immunogenicity of heterologous boosting with orally aerosolised or intramuscular Ad5-nCoV vaccine and homologous boosting with inactivated vaccines (BBIBP-CorV or CoronaVac) in children and adolescents: a randomised, open-label,
Liu X, journal of infection, 2023 a	"Persistence of immune responses after heterologous and homologous third COVID-19 vaccine dose schedules in the UK: eight-month analyses of the COV-BOOST trial."
Nolan T, Lancet, 2023	Interim Results from a Phase I Trial of Novel SARS-CoV-2 Beta Variant Receptor-Binding Domain Recombinant Protein and mRNA Vaccines as a 4th Dose Booster
Oda Y, medRxiv, 2023	Booster dose of self-amplifying SARS-CoV-2 RNA vaccine vs. mRNA vaccine: a phase 3 comparison of ARCT-154 with Comirnaty
Roa CC, J Infect Dis, 2023	Superior boosting of neutralizing titers against Omicron SARS-CoV-2 variants by heterologous SCB-2019 vaccine vs a homologous booster in CoronaVac-primed adults
Tan NH, Lancet inf dis, 2023	Immunogenicity of bivalent omicron (BA.1) booster vaccination after different priming regimens in health-care workers in the Netherlands (SWITCH ON): results from the direct boost group of an open-label, multicentre, randomised controlled t
Wu J-D, Lancet Infect Dis, 2023	Safety, immunogenicity, and efficacy of the mRNA vaccine CS-2034 as a heterologous booster versus homologous booster with BBIBP-CorV in adults aged â‰¥18 years: a randomised, double-blind, phase 2b trial.

COVID-19 vaccine effectiveness(Randomized evidence)

Methods

meta-COVID

Vaccine types

COVID-19 BOOSTER DOSE VACCINATION: updated daily

COVID-19 PRIME VACCINATION: Last search date December 14, 2022.

Trials reports under extraction

Description of primary studies

Search studies

COVID-19 vaccine effectiveness
(Randomized evidence)