Trial TCTR20210907003, TCTR20211102006
Publication Niyomnaitham S, Vaccines, 2022
Dates: 2021-09-01 to 2022-02-28
Funding: Public/non profit (Health Systems Research Institute, Thailand.)
Conflict of interest: no COI

Methods
RCT
Location : Single center / Thailand
Follow-up duration (months): 0.5
BNT162b2 0.05 mL intradermal booster after CoronaVac primary series (n = 45)
ChAdOx1 0.1 mL intradermal booster after CoronaVac primary series (n = 45)
Inclusion criteria
  • Healthy adults aged 18 years or older
  • received homologous two-dose primary series intramuscular vaccination of CoronaVac 4–12 weeks prior to recruitment.
Exclusion criteria
  • Confirmed history of SARS-CoV-2 infection
  • received current prophylactic treatment or investigational agents against COVID-19 within 90 days
  • unstable underlying diseases that may compromise the immune responses
  • history of vaccine hypersensitivity
  • pregnant
  • immunocompromised or receiving immunosuppressive agents.
Interventions
Intervention
1 intradermal dose 1 × 10^10 viral particles ChAdOx1, 4-12 weeks after primary CoronaVac series
Control
1 intradermal dose 5 mcg BNT162b2, 4-12 weeks after primary CoronaVac series
Participants
Randomized
90 participants
Characteristics of participants
Type of participants: Healthy adults
N=90
41 males
Children: 0
Pregnant women: 0
Immunocompromized patients: 0
Mean age:
Age range: NR
Description of participants
Healthy adults with no known history of previous SARS-CoV-2 infection at a single center in Thailand.
Primary outcome
In the register
Immune response - IgG level 2 wk after vaccination
In the report
anti-RBD SARS-CoV-2 IgG antibody geometric mean concentrations (GMC) two weeks after vaccine injection
Documents
available

Protocol

NR

Statistical plan

*

Data-sharing stated: Yes
Data accessibility: The data presented in this study are available upon request from the corresponding author. Correspondence: Kulkanya Chokephaibulkit MD - kulkanya.cho@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 published article, the trial registries and supplementary appendices were used in data extraction and assessment of risk of bias. Neither protocol nor statistical analysis plan was available. The outcome used for sample size calculation in the article reflected the primary outcome in the registry. The study included six arms in an initial exploratory phase and three arms in an extension phase, which focused on participants with CoronaVac and ChAdOx1 primary schedules, the most common in Thailand. Two arms comprised participants with CoronaVac prime schedule and the third a ChAdOx1 prime schedule. This third arm was not randomized for the extension phase and thus was not extracted. The trial (n = 90) achieve its target sample size (n = 90).