Trial NCT05049226
Publication Niyomnaitham S, medRxiv, 2022
Dates: 2021-09-24 to 2021-10-14
Funding: Public/non profit (This study was funded by the Program Management Unit for Competitiveness Enhancement (PMU-C) National research, National Higher Education, Science, Research and Innovation Policy Council, Thailand through Clinixir Ltd. (CRO))
Conflict of interest: no COI

Methods
RCT
Location : Multicenter / Thailand
Follow-up duration (months): 3
2.5 × 10^10 vp ChAdox1-S (half dose) (n = 312)
5 × 10^10 vp ChAdOx1-S (full dose) (n = 307)
15 mcg BNT162b2 (half dose) (n = 316)
30 mcg BNT162b2 (full dose) (n = 308)
Inclusion criteria
  • Healthy adults aged 20 years or older
  • either 60-days-to-<90 days, 90-days-to-<120 days, or 120-to-180 days (‘intervals’) post-receipt of CoronaVac primary-series (21-28 days apart)
  • no history of fever or symptoms within 7 days of enrolment
  • not pregnant
  • written informed consent.
Exclusion criteria
  • A history of COVID-19 infection within 3 months of enrolment
  • contraindication to ChAdOx1 or BNT162b2
  • confirmed or suspected immunosuppressive or immunodeficient state.
Interventions
Intervention
1 IM dose of 2.5 × 10^10 vp ChAdOx1/AZD1222 in 0.25 mL, 2-6 months after CoronaVac primary schedule
1 IM dose of 15 mcg BNT162b2 (half dose) in 0.25 mL, 2-6 months after CoronaVac primary schedule
Control
1 IM dose of 5 × 10^10 vp ChAdOx1/AZD1222 in 0.5 mL, 2-6 months after CoronaVac primary schedule1 IM dose of 30 mcg BNT162b2 (full dose) boost, 2-6 months after CoronaVac primary schedule
Participants
Randomized
1243 participants
Characteristics of participants
Type of participants: Healthy adults
N=1243
529 males
Children: 0
Pregnant women: 0
Immunocompromized patients: 0
Mean age:
Age range: NR
Description of participants
Healthy adults without recent (3 months) COVID-19 at 7 centers in Thailand.
Primary outcome
In the register
1) GMT Anti-S IgG at baseline and after vaccination at day 28, day 60 and day 90; 2) GMFR changed from baseline in anti-S IgG GMT at 28,60 and 90 days after vaccination; 3) Frequency and percentage of participants with seroresponses in anti-S IgG titer as defined by (1) a ≥ 4-fold increase from baseline at 28, 60 and 90 days after vaccination (2) a ≥ 10-fold increase from baseline at 28, 60 and 90 days after vaccination; 4) GMT against SARS-Cov-2 pseudovirus (PVNT) Neutralizing antibody titer 50 at baseline and after vaccination at day 28 and day 90; 5) GMFR changed from baseline in NT50 against SARS-CoV-2 pseudovirus at 28 and 90 days vaccination; 5) Frequency and percentage of solicited reportable local adverse events (pain or tenderness, erythema, swelling or induration) of vaccination; 6) Frequency and percentage of solicited reportable systemic adverse events (fever, headache, fatigue or malaise, myalgia, arthralgia, nausea or vomiting) of vaccination; 7) Frequency and percentage of all unsolicited AEs; 8) Frequency and percentage of SAEs throughout the entire study period
In the report
1) IgG levels against Anti-S RBD, at baseline, 28, 60 and 90 days after the third-dose/booster; 2) functional (neutralizing) humoral immune response, elicited by each regimen was also assessed by the PNA at baseline, 28, and 90 days post-third dose; 3) Third-dose vaccination safety and tolerability were evaluated at different intervals.
Documents
available

Protocol

NR

Statistical plan

*

Data-sharing stated: Yes
Data accessibility: All data produced in the present study are available upon reasonable request to the authors. Punnee Pitisuttithum - punnee.pit@mahidol.ac.th
Risk of bias
Overall
The overall risk of bias reported in the table corresponds to the highest risk of bias for the outcomes assessed for the systematic review
Some concerns
General comment In addition to the pre-print article, the prospective trial registry was used in data extraction and assessment of risk of bias. Neither protocol nor statistical analysis plan was available. The primary outcomes in the article reflect those in the registries. The trial (n = 1243) achieved its target sample size (n = 988).