Variant-Specific IgA Protects Against Omicron Infection

J Infect Dis. 2024 Aug 16;230(2):e287-e291. doi: 10.1093/infdis/jiad525.

Abstract

Background: The emergence of rapidly evolving severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants, coupled with waning vaccine-induced immunity, has contributed to the rise of vaccine breakthrough infections. It is crucial to understand how vaccine-induced protection is mediated.

Methods: We examined 2 prospective cohorts of mRNA vaccinated and boosted individuals during the Omicron wave of infection in Singapore.

Results: We found that individuals who remain uninfected over the follow-up period had a higher variant-specific IgA, but not IgG, antibody response at 1 month after booster vaccination, compared with individuals who became infected.

Conclusions: We conclude that IgA may have a potential contributory role in protection against Omicron infection. Clinical Trials Registration . NCT05142319.

Keywords: COVID-19; IgA; Omicron; S protein; SARS-CoV-2; antibodies; mRNA vaccine.

Publication types

  • Clinical Trial, Phase IV

MeSH terms

  • Adult
  • Antibodies, Viral* / blood
  • Antibodies, Viral* / immunology
  • COVID-19 Vaccines* / immunology
  • COVID-19* / immunology
  • COVID-19* / prevention & control
  • Female
  • Humans
  • Immunization, Secondary
  • Immunoglobulin A* / immunology
  • Immunoglobulin G / blood
  • Immunoglobulin G / immunology
  • Male
  • Middle Aged
  • Prospective Studies
  • SARS-CoV-2* / immunology
  • Singapore / epidemiology
  • Vaccination

Substances

  • Antibodies, Viral
  • COVID-19 Vaccines
  • Immunoglobulin A
  • Immunoglobulin G

Supplementary concepts

  • SARS-CoV-2 variants

Associated data

  • ClinicalTrials.gov/NCT05142319