Third Dose Vaccination With AstraZeneca or Pfizer COVID-19 Vaccine Among Adults Received Sinovac COVID-19 Vaccine

Summary

This prospective, multi-center, randomized, observer-blind Phase 2 study. A total of 1320 participants will be divided into 2 groups (660 each) receiving either full dose or half dose of either AZ or PF. Each group is further stratified into 3 subgroups according to three interval duration in term of days after second dose of SV for 60 to less than 90 days, 90 to less than120 days and 120 to 180 days. Each group will be randomized to receive either AZ or PF in 1:1 ratio. Subjects who fulfilled eligibility criteria will be randomly assigned to receive either full dose or half dose of AZ or PF in 1:1 ratio as an IM injection in the deltoid muscle at Visit 1 (V1). Subjects will be follow-up for assessing immunity at day 28 (V3), day 60 (V4) and day 90 (V5) and for safety at day 7 (V2), day 28 (V3), day 60 (V4) and day 90 (V5). At least 50% from each subgroup will be randomly selected to provide additional blood at baseline (V1, day 0) and day 28 (V3) to be used for assessment of T-cell-mediated immunity (CMI)

Timeline

Start

2021-09-24

Primary completion

2022-02-22

Completion

2022-02-22

Drugs

Indications