Summary of findings:

ChAdOx1 compared to MenACWY for vaccination against COVID-19

Patient or population:
Setting:
Intervention:
Comparison:

Outcomes

Anticipated absolute effects* (95% CI)

Relative effect
(95% CI)

№ of participants
(studies)

Certainty of the evidence
(GRADE)

Comments

Risk with MenACWY

Risk with ChAdOx1

Incidence of participants with positive test for SARS-CoV-2 infection b,c
4,033 per 100,000
1855 per 100,000
(1,532 to 2,218)
Rate ratio 0.46
(0.38 to 0.55)
17177
(1 RCT)
d

MODERATE
e,f
Vaccine efficacy 54.10% (95%CI 44.70% to 61.90%)
Incidence of symptomatic COVID-19 confirmed with positive test for SARS-CoV-2 b,c
2,890 per 100,000
954 per 100,000
(752 to 1,243)
Rate ratio 0.33
(0.26 to 0.43)
17177
(1 RCT)
d

MODERATE
e,f
Vaccine efficacy 66.70% (95%CI 57.40% to 74.00%)
Incidence of hospitalization or death due to confirmed COVID-19 b,c
74 per 100,000
4 per 100,000
(0 to 65)
RR 0.05
(0.00 to 0.88)
24512
(1 RCT)
d

LOW
f,g
Severe or critical disease due to COVID-19 b,h
9 per 100,000
3 per 100,000
(0 to 68)
RR 0.33
(0.01 to 7.98)
23745
(1 RCT)
i

VERY LOW
f,j
All-cause mortality b,k
33 per 100,000
16 per 100,000
(3 to 89)
RR 0.49
(0.09 to 2.66)
24244
(1 RCT)
i

VERY LOW
f,j
Incidence of any adverse events b,l
1,075 per 100,000
795 per 100,000
(602 to 1,032)
RR 0.74
(0.56 to 0.96)
23745
(1 RCT)
i

MODERATE
f
Incidence of serious adverse events (SAEs) b,k
1,062 per 100,000
881 per 100,000
(679 to 1,136)
RR 0.83
(0.64 to 1.07)
24244
(1 RCT)
i

LOW
f,m
*The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).

CI: Confidence interval; RR: Risk ratio
GRADE Working Group grades of evidence
High certainty: We are very confident that the true effect lies close to that of the estimate of the effect
Moderate certainty: We are moderately confident in the effect estimate: The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different
Low certainty: Our confidence in the effect estimate is limited: The true effect may be substantially different from the estimate of the effect
Very low certainty: We have very little confidence in the effect estimate: The true effect is likely to be substantially different from the estimate of effect

Explanations

a. Last updated: February 26, 2021
b. Pooled interim analysis of COV001, COV002, COV003 and COV005
c. >14 days after second dose; median follow-up 4 months
d. AstraZeneca: Voysey M, 2021
e. Despite some concerns with deviations from intervention, not downgraded for risk of bias.
f. Indirectness downgraded by one level: data are from an interim analysis of the trial, with a short duration of follow-up. Estimates may change over a longer duration of follow-up.
g. Imprecision downgraded by one level: due to few events observed.
h. >14 days after second dose; median follow-up 2 months
i. AstraZeneca: Voysey M, 2020
j. Imprecision downgraded by 2 levels: due to wide confidence interval consistent with the possibility for benefit and the possibility for harm and few events.
k. mean follow-up 4.1 months
l. median follow-up 3.4 months
m. Imprecision downgraded by 1 level: due to wide confidence interval consistent with the possibility for no effect and the possibility for benefit.