A Phase II Trial to Evaluate the Safety and Immunogenicity of SARS-CoV-2 Monovalent and Multivalent RNA-based Vaccines in Healthy Subjects

This trial consists of three parts, Part A, Part B, and Part C, and will evaluate the safety
and immunogenicity of a third booster injection of the multivalent vaccine BNT162b2 (B.1.1.7
+ B.1.617.2), and the safety and immunogenicity of a third booster injection of the
monovalent vaccine BNT162b2 (B.1.617.2) or BNT162b2 (B.1.1.7), in participants who have
received two doses of the parent vaccine BNT162b2 at 30 µg, at least 6 months after the
second dose of BNT162b2. It will also evaluate the safety and immunogenicity of a three-dose
regimen of BNT162b2 (B.1.1.7 + B.1.617.2) in participants who have not received prior
Coronavirus Disease 2019 (COVID-19) vaccination. In addition, the safety and immunogenicity
of BNT162b2 (B.1.1.529.1) or BNT162b2 given as a third or fourth vaccine dose to RNA COVID-19
vaccine-experienced participants with history of SARS-CoV-2 infection will be evaluated and
contrasted with the natural immune response reached after infection with the SARS-CoV-2
Omicron variant.