Background: Data from the dose-escalating phase 1 trials from the COVID-19 mRNA vaccines being authorized in the European Union since December 2020, BNT162b2 (Comirnaty®; Pfizer- BioNTech) indicate that for the age group 18-55 years a lower dose of the vaccine can induce the same immune response as the full dose.~Method: This is a randomized multicenter phase IV dose-optimization study evaluating the safety and immunogenicity of demi-doses of a COVID-19 mRNA vaccine being authorized in the European Union since December 2020, BNT162b2 (Comirnaty®; Pfizer- BioNTech) in healthy adults up to age 55 year. The study will be performed in employees of Mensura EDPB at five different sites.~Objectives: The primary outcome is the level of binding antibodies for RBD 28 days after the second dose. Secondary outcomes are safety and reactogenicity after vaccination. The neutralizing antibodies and the cellular immunity 28 days after second dose will be assessed. Humoral and cellular immunity will be measured 180 and 365 days after first dose.
This is a randomized phase IV dose-optimization study evaluating the safety and immunogenicity of two doses of COVID-19 mRNA vaccines being authorized in the European Union since December 2020: Vaccine BNT162b2 (Comirnaty®; Pfizer-BioNTech) in healthy adults up to age 55 year. Immunogenicity will be measured 28 days after first and second dose, and day 180 and day 365 after first vaccination of 20 and 30 mcg of BNT162b2. The primary outcome is the level of binding antibodies for RBD 28 days after the second dose.