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.

Group A trial participants were randomized 2:1 to BNT162b2s01:Comirnaty. Group B trial participants were allocated to trial treatment without active randomization and selected participants were asked to participate in the detailed immunogenicity assessment based on their parent trial cohort.

Eligibility Criteria:
Inclusion Criteria:

* Had given informed consent by signing the informed consent form (ICF) before initiation of any trial-specific procedures.
* Were willing and able to comply with scheduled visits, treatment schedule, laboratory tests, lifestyle restrictions (including those requested by the German and federal Governments, e.g., to follow good practices to reduce chances of spreading COVID 19), and other requirements of the trial.
* Have received BNT162 vaccine candidates in the BNT162-01 or BNT162-04 trials.
* Remained overall healthy (i.e., has not medically deteriorated significantly since participation in the parent trial, is not anticipated to die in the next 26 weeks, and is able to provide blood as specified by the trial without anticipated, deleterious medical consequences) in the clinical judgment of the investigator based on medical history and physical examination. Screening clinical laboratory tests are to assess the participants' "new baseline" unless required for eligibility. Note: in particular, caution should be used with a subject who has a history of cardiovascular disease, e.g., myocarditis, pericarditis, myocardial infarction, congestive heart failure, cardiomyopathy, or clinically significant arrhythmia.
* Agreed not to enroll in another trial of an IMP, starting after Visit 0 and continuously until Visit 5 (Day 50).
* Less than 18 months have passed since their last IMP injection in their parent trial.
* If they received 30 μg Comirnaty twice in the BNT162-01 trial, Visit 1 in this trial is ≥24 weeks after their last IMP injection, unless the subject is a Cohort 13 transplant subject of the BNT162-01 trial.
* If they received any other BNT162 vaccine candidate than Comirnaty in the BNT162-01 or BNT162-04 trial or are a Cohort 13 transplant subject, Visit 1 in this trial is ≥12 weeks after their last IMP injection.
* Have not been diagnosed with SARS-CoV-2 infection in the 12 weeks prior to day 1 (baseline). Participants who screen-fail on this criterion may be rescreened.

Exclusion Criteria:

* Have received any SARS-CoV-2 vaccine outside of the BNT162-01 or BNT162-04 trials.
* Have had a known allergy, hypersensitivity, or intolerance to the planned IMP including any excipients of the IMP.
* Have had a current febrile illness (body temperature ≥38.0°C) or other acute illness within 48 hours prior to day 1/IMP injection in this trial. Participants who screen-fail on this criterion may be rescreened.
* Have received a live or live attenuated vaccine within 30 days prior to day 1/IMP injection, or any other vaccination within 14 days prior to day 1/IMP injection. Participants who screen-fail on this criterion may be rescreened.
* Have had an ongoing AE assessed as related to any BNT162-01 or BNT162-04 trial vaccine.