Life (Oct 2023)

Risk of SARS-CoV-2 Reinfection 3 Years after the Start of the Pandemic: A Population-Level Observational Study

  • Cecilia Acuti Martellucci,
  • Maria Elena Flacco,
  • Graziella Soldato,
  • Giuseppe Di Martino,
  • Roberto Carota,
  • Annalisa Rosso,
  • Marco De Benedictis,
  • Graziano Di Marco,
  • Rossano Di Luzio,
  • Francesco Lisbona,
  • Antonio Caponetti,
  • Lamberto Manzoli

DOI
https://doi.org/10.3390/life13112111
Journal volume & issue
Vol. 13, no. 11
p. 2111

Abstract

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The risk of SARS-CoV-2 reinfections changes as new variants emerge, but the follow-up time for most of the available evidence is shorter than two years. This study evaluated SARS-CoV-2 reinfection rates in the total population of an Italian province up to three years since the pandemic’s start. This retrospective cohort study used official National Healthcare System data on SARS-CoV-2 testing and vaccinations, demographics, and hospitalizations in the Province of Pescara, Italy, from 2 March 2020 to 31 December 2022. A total of 6541 (5.4%) reinfections and 33 severe and 18 lethal COVID-19 cases were recorded among the 121,412 subjects who recovered from a primary infection. There were no severe events following reinfection in the young population, whereas 1.1% of reinfected elderly died. A significantly higher reinfection risk was observed among females; unvaccinated individuals; adults (30–59 y); and subjects with hypertension, COPD, and kidney disease. Up to three years after a primary SARS-CoV-2 infection, the majority of the population did not experience a reinfection. The risk of severe COVID-19 following a reinfection was very low for young and adult individuals but still high for the elderly. The subjects with hybrid immunity showed a lower reinfection risk than the unvaccinated.

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