Epidemiology of reinfections by SARS-CoV-2 variants during the third and fourth waves of the COVID-19 pandemic.

Introduction: The coronavirus disease 2019 (COVID-19) pandemic is a global health concern and has persisted through the emergence of variants that have caused subsequent waves of COVID-19 due to the high dispersion and contagiousness of the virus. The aim of this work was to analyze the epidemiology of the cases of reinfection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants during the third and fourth wave of the COVID-19 pandemic at the Hospital Juárez de México (HJM).

Methodology: A prospective study of the cases of SARS-CoV-2 reinfection, variants detected, symptoms, and associated comorbidities was carried out on 1,347 patients who attended the HJM from September 2021 to July 2022.

Results: 760 (56.4%) and 587 (43.6%) patients were negative and positive for SARS-CoV-2, respectively. The Omicron variant was the most frequent and the most common symptoms were: cough (80%), headache (61.32%), fever (51.6%), and dyspnea (40%). A higher proportion of females were vaccinated, ranging from one dose to the complete schedule. The factors that were associated with a greater risk of death from complications of SARS-CoV-2 reinfection were male gender, diabetes mellitus, and arterial hypertension.

Conclusions: Females were the most susceptible to an Omicron reinfection event, even though they were vaccinated. However, the risk of death was higher when the patient was male; being male was a potential risk factor for death from COVID-19 and comorbidities.