Revista de Investigación Clínica (Oct 2022)

Significant rise in SARS-CoV-2 reinfection rate in vaccinated Hospital workers during the omicron wave: A prospective cohort study

  • Eric Ochoa-Hein,
  • Patricia E. Leal-Morán,
  • Karen A. Nava-Guzmán,
  • Abril T. Vargas-Fernández,
  • José F. Vargas-Fernández,
  • Fabricio Díaz-Rodríguez,
  • Joel Armando Rayas-Bernal,
  • Ricardo González-González,
  • Pavel Vázquez-González,
  • Martha A. Huertas-Jiménez,
  • Sandra Rajme-López,
  • Pilar Ramos-Cervantes,
  • Violeta Ibarra-González,
  • Luis A. García-Andrade,
  • Fernando Ledesma-Barrientos,
  • Alfredo Ponce-de-León,
  • José Sifuentes-Osornio,
  • Arturo Galindo-Fraga

DOI
https://doi.org/10.24875/RIC.22000159
Journal volume & issue
Vol. 74, no. 4

Abstract

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Background: Relatively low SARS-CoV-2 reinfection rates have been reported in vaccinated individuals, but updates considering the Omicron variant are lacking. Objective: The objective of the study was to provide a current estimate of the SARS-CoV-2 reinfection rate in a highly immunized population. Methods: A prospective cohort of Mexican hospital workers was followed (March 2020-February 2022). Reinfection was defined as the occurrence of two or more episodes of COVID-19 separated by a period of ≥ 90 days without symptoms. The reinfection rate was calculated as the number of reinfection episodes per 100,000 persons per day. Results: A total of 3732 medical consultations were provided to 2700 workers, of whom 1388 (51.4%) were confirmed COVID-19 cases. A total of 73 reinfection cases were identified, of whom 71 (97.3%) had completed their primary vaccination series and 22 (30.1%) had had a booster dose before the second episode. The overall reinfection rate was 23.1 per 100,000 persons per day (as compared to a rate of 1.9 per 100,000 persons per day before the Omicron wave). Conclusions: The SARS-CoV-2 reinfection rate rose significantly during the Omicron wave despite a high primary vaccination coverage rate. Almost one-third of reinfected workers had a vaccine booster ≥ 14 days before the last COVID-19 episode.

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