Viral Load Dynamics in SARS-CoV-2 Omicron Breakthrough Infections

J Infect Dis. 2022 Nov 11;226(10):1721-1725. doi: 10.1093/infdis/jiac290.


To determine viral dynamics in Omicron breakthrough infections, we measured severe acute respiratory syndrome coronavirus 2 RNA in 206 double-vaccinated or boostered individuals. During the first 3 days following the onset of symptoms, viral loads were significantly higher (cycle threshold [Ct], 21.76) in vaccinated compared to boostered (Ct, 23.14) individuals (P = .029). However, by performing a longitudinal analysis on 32 individuals over 14 days, no difference in the viral load trajectory was observed between double-vaccinated and boostered patients. Our results indicate that booster immunization results in a reduction in detectable viral loads without significantly changing viral load dynamics over time.

Keywords: Omicron; booster immunization; breakthrough infection; vaccination; viral load.

MeSH terms

  • Antibodies, Viral
  • COVID-19*
  • Humans
  • SARS-CoV-2
  • Serologic Tests
  • Viral Load


  • Antibodies, Viral