Trial TCTR20210722003
Publication Nanthapisal S, Vaccine, 2022
Dates: 2021-07-23 to 2021-08-30
Funding: Public/non profit (Ratchadapisek Sompoch Endowment Fund, Chulalongkorn University and Faculty of Medicine, Thammasat University.)
Conflict of interest: no COI

Methods
RCT
Location : Multicenter / Thailand
Follow-up duration (months): 3
Low dose ChAdOx1-S (n = 211)
High dose ChAdOx1-S (n = 211)
Inclusion criteria
  • Healthy adults
  • age 18 – 59 years old
  • completed two doses of CoronaVac for more than 60 days, with interval of 21 – 28 days
  • written informed consent.
Exclusion criteria
  • Received any immunosuppressants or blood products within 3 months or any vaccines within 2 weeks before study enrollment
  • or with previous SARS-CoV-2 infection.
Interventions
Intervention
1 IM booster dose of 5 × 10^10 VP ChAdOx1-S ≥60 days (median 77) after 2-dose schedule of CoronaVac
Control
1 IM booster dose of 2.5 × 10^10 VP ChAdOx1-S ≥60 days (median 74) after 2-dose schedule of CoronaVac
Participants
Randomized
422 participants
Characteristics of participants
Type of participants: Healthy adults
N=422
202 males
Children: 0
Immunocompromized patients: 0
Mean age:
Age range: NR
Description of participants
Healthy adult volunteers with no history or current infection with SARS-CoV-2 who had completed two doses of CoronaVac at 2 centres in Thailand.
Primary outcome
In the register
1) Anti-S-RBD Antibody level day 0 and 14 after vaccination; 2) sVNT for neutralizing antibody day 0 and 14 after vaccination; 3) Antigen-specific cellular immunity day 0 and 14 after vaccination
In the report
1) GMR of sVNT against wild type and delta variant; 2) anti-S-RBD IgG, comparing low dose to standard dose at day 14 and 28 after booster
Documents
available

Protocol

NR

Statistical plan

*

Data-sharing stated: NR
Data accessibility: Thanyawee Puthanakit; thanyawee.p@chula.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 published article, the prospective study registry and supplementary data were used in data extraction and risk of bias assessment. The protocol and statistical analysis plan were not available. The registry has one additional primary outcome (Antigen-specific cellular immunity) which is a secondary outcome in the paper. The time points for these outcomes are Day 0 and 14 in the registry and Day 14 and 28 in the paper. The target sample size (n=400) specified in the registry was achieved (n=422)."