Enhancement of Humoral and Cellular Immunity Against Severe Acute Respiratory Syndrome Coronavirus 2 by a Third Dose of BNT162b2 Vaccine in Japanese Healthcare Workers

J Infect Dis. 2023 Jan 11;227(2):221-225. doi: 10.1093/infdis/jiac344.

Abstract

The Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has raised concerns regarding vaccine effectiveness. We investigated humoral and cellular immune responses against SARS-CoV-2 in healthcare workers before and after a third (booster) dose of the BNT162b2 messenger RNA vaccine. It significantly enhanced both humoral and cellular immunity in previously uninfected individuals. However, cellular immunity was not enhanced in previously infected persons, suggesting that 3 antigenic stimuli by vaccination or natural infection reached a plateau of cellular immunity. Even with reinforced immunity to SARS-CoV-2, we confirmed several postbooster breakthrough cases caused by the Omicron variant.

Keywords: BNT162b2 vaccine; Omicron sublineages; T-cell immunity; neutralization antibody.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Viral
  • BNT162 Vaccine
  • COVID-19* / prevention & control
  • East Asian People
  • Health Personnel
  • Humans
  • Immunity, Cellular
  • Immunity, Humoral
  • SARS-CoV-2
  • Vaccination
  • Vaccines*

Substances

  • BNT162 Vaccine
  • Vaccines
  • Antibodies, Viral

Supplementary concepts

  • SARS-CoV-2 variants