OPEN ACCESS EDITED BY Two-year follow-up of the COVID-pandemic in Mexico

Background: After the initial outbreak in China in late 2019, WHO declared COVID-19 a pandemic on March 11, 2020. This study describes the first two years of the pandemic in Mexico. Design and methods: Population-based longitudinal analysis using Mexico’s national COVID-19 registry (SISVER) to track confirmed cases (CCs), hospitalizations, deaths, and symptoms in relation to health policies and circulating variants. Logistic regression assessed risk factors for severity (hospital admission, death). Results: From March 2020 to March 2022, Mexico experienced four epidemic waves. Out of 5,702,143 CCs, 680,063 (11.9%) were hospitalized and 324,436 (5.7%) died. Although susceptibility did not differ by sex, males had higher risk of death (CFP 7.3% vs 4.2%) and admission (HP 14.4% vs 9.5%). Severity increased with age; the 60+ group had the highest risks, with adjusted ORs up to 9.63 and 53.05 (for admission and death, respectively). The presence of any comorbidity approximately doubled the odds (admission OR ≈2.40; death OR ≈2.38), with hypertension-diabetes the riskiest combination. While wave peaks in CCs increased over time, adjusted odds for severe outcomes decreased progressively across waves, reaching ~0.15 (95% CI: 0.13–0.18) in wave 4 for both admission and death. Conclusion: Government health policies, evolving clinical management, vaccination, treatments, and changing variant severity contributed to decreased hospitalizations and deaths over time, especially among older adults at highest risk. Comorbidities significantly increased the risk of severe illness, particularly the hypertension-diabetes combination.