A Trial Investigating the Safety and Effects of One or Two Additional Doses of Comirnaty or One Dose of BNT162b2s01 in BNT162-01 or BNT162-04 Trial Subjects

Trial to evaluate the safety and immunogenicity of one or two boosting doses of Comirnaty or one dose of BNT162b2s01 (Variant of concern \[VOC\] strain B.1.351) in BNT162-01 trial participants, or two boosting doses of Comirnaty in BNT162-04 trial participants. Trial participants from BNT162-01 who received two injections of 30 μg Comirnaty were randomized 2:1 to one booster injection (BNT162b2s01: Comirnaty). Trial participants in either the trial BNT162-01 or BNT162-04 who did not receive the full two vaccinations of 30 μg Comirnaty were offered two injections of 30 μg Comirnaty as per the conditional marketing authorization. All potential rollover volunteers must enroll in this trial within less than 18 months of their last injection of a BNT162 candidate vaccine in the parent BNT162-01 or BNT162-04 trials.