Vaccines (Nov 2023)

Age and Comorbidities as Risk Factors for Severe COVID-19 in Mexico, before, during and after Massive Vaccination

  • Lenin Domínguez-Ramírez,
  • Francisca Sosa-Jurado,
  • Guadalupe Díaz-Sampayo,
  • Itzel Solis-Tejeda,
  • Francisco Rodríguez-Pérez,
  • Rosana Pelayo,
  • Gerardo Santos-López,
  • Paulina Cortes-Hernandez

DOI
https://doi.org/10.3390/vaccines11111676
Journal volume & issue
Vol. 11, no. 11
p. 1676

Abstract

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During 2020–2023, Mexico had a large COVID-19 emergency with >331,000 adult deaths and one of the highest excess mortalities worldwide. Age at COVID-19 death has been lower in Mexico than in high-income countries, presumably because of the young demographics and high prevalence of chronic metabolic diseases in young and middle-aged adults. SARS-CoV-2 vaccination covered 85% of adults with at least one dose and 50% with booster(s) up to April 2022. No new vaccination efforts or updated boosters were introduced until October 2023; thus, we explored the public health impact of massive SARS-CoV-2 vaccination against ancestral strains and asked whether their real-world protection has persisted through time. We compared three periods with respect to vaccine roll-outs: before, during and after vaccine introduction in a national retrospective cohort of >7.5 million COVID-19 cases. The main findings were that after vaccination, COVID-19 mortality decreased, age at COVID-19 death increased by 5–10 years, both in populations with and without comorbidities; obesity stopped being a significant risk factor for COVID-19 death and protection against severe disease persisted for a year after boosters, including at ages 60–79 and 80+. Middle-aged adults had the highest protection from vaccines/hybrid immunity and they more than halved their proportions in COVID-19 deaths.

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