Highlights: Phase 1/2 Study of COVID-19 RNA Vaccine BNT162b1 in Adults

12 August 2020

  • In March 2020, the World Health Organization (WHO) declared a pandemic of coronavirus disease 2019 (COVID-19).
  • The causative agent of COVID-19 is the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
  • A vaccine is urgently needed due to the rising cases and deaths reported globally.
  • This study reports the available safety, tolerability, and immunogenicity data from an ongoing placebo-controlled, observer-blinded dose escalation study among 45 healthy adults.
  • The healthy adults include 18 to 55 years of age.
  • The healthy adults were randomized to receive 2 doses, separated by 21 days, of 10 µg, 30 µg, or 100 µg of BNT162b1.
  • BNT162b1 is a lipid nanoparticle-formulated, nucleoside-modified mRNA vaccine that encodes trimerized SARS-CoV-2 spike glycoprotein receptor-binding domain (RBD).
  • Local reactions and systemic events were dose-dependent, generally mild to moderate, and temporary.
  • A second vaccination with 100 µg was not administered due to increased reactogenicity and a lack of meaningfully increased immunogenicity after a single dose compared to the 30 μg dose.
Reactogenicity refers to the property of a vaccine of being able to produce common, “expected” adverse reactions, especially excessive immunological responses and associated signs and symptoms, including fever and sore arm at injection site.

  • RBD-binding IgG concentrations and SARS-CoV-2 neutralizing titers in sera increased with dose level and after a second dose.
  • Geometric mean neutralizing titers reached 1.9- to 4.6-fold that of a panel of COVID-19 illness-recovering human sera at least 14 days after a positive SARS-CoV-2 polymerase chain reaction.
  • These results support further evaluation of this mRNA vaccine candidate.

Keywords: COVID-19, RNA vaccine, coronavirus vaccine, COVID-19 vaccine, what is BNT162b1, pfizer vaccine, biontech vaccine, pfizer coronvirus drug, biontech coronavirus drug


Mulligan, M.J., Lyke, K.E., Kitchin, N. et al. Phase 1/2 study of COVID-19 RNA vaccine BNT162b1 in adults. Nature (2020). https://doi.org/10.1038/s41586-020-2639-4. https://www.nature.com/articles/s41586-020-2639-4


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