IFNγ-producing CD4
The four study groups included participants who previously received two doses of CoronaVac and were randomly assigned to receive a third dose of CoronaVac (CC-C) or BNT162b2 (CC-B), and participants who previously received two doses of BNT162b2 and were randomly assigned to receive a third dose of CoronaVac (BB-C) or BNT162b2 (BB-B). Data were available from a random subset of 20 participants selected from each study group (