Safety and Effects of an Investigational COVID-19 Vaccine as Booster in Healthy People

Protocol summary

This is an exploratory Phase I, randomized, observer-blind, active-controlled, dose-escalation trial to evaluate four dose levels (DLs) of BNT162b4 given in combination with BNT162b2 Bivalent (original/Omicron BA.4/BA.5) to select a safe and tolerable dose and to evaluate BNT162b4 + BNT162b2 Bivalent (original/Omicron BA.4/BA.5) when given as Dose 1 and Dose 2 (booster) in Cohorts 1 and 2 and BNT162b4 + BNT162b2 Monovalent (OMI XBB.1.5) when given as Dose 2 (booster) in Cohorts 3a, 3b, 4a, and 4b, and 30 μg BNT162b4 when given alone as Dose 1 and Dose 2 in Cohort 5. The trial will use a staggered dosing process schema, i.e., enrollment into the next higher dose level is done sequentially and subject to safety data from the previous dose levels, with sentinel participants in Cohorts 1, 2, 3a, and 4a. Cohort 3b investigating the same dose level as cohort 3a but in participants aged \>55 years will be opened after safety data for participants aged 18-55 years in Cohort 3a has been reviewed. Enrollment into Cohorts 4a and 4b will be opened after safety data for Cohort 3a and 3b has been reviewed. Cohort 5 participants will not be randomized and will receive two doses of BNT162b4 alone after which a safety review will be performed after all participants have received Dose 2 in this cohort. BNT162b4 plus BNT162b2 Bivalent (original/Omicron BA.4/BA.5)/Monovalent (OMI XBB.1.5) will be co-administered (as a single injection). BNT162b4 alone will be administered as a single injection.