Predictors of severe symptomatic laboratory-confirmed SARS-CoV-2 reinfection

The aim of the study was to evaluate factors predicting severe symptomatic laboratory-confirmed (via Reverse transcription polymerase chain reaction, RT-PCR polymerase chain reaction) severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reinfection.

This is a nationwide retrospective cohort study that was conducted in Mexico.

Data from 258 reinfection cases (at least 28 days between both episodes onset) were analyzed. We used risk ratios (RRs) and 95% confidence intervals (CIs) to evaluate predictors of severe (dyspnea requiring hospital admission) secondary SARS-CoV-2 infection.

The risk of severe disease was 14.7%, and the observed overall fatality rate was 4.3%. Patients with more serious primary disease were more likely to develop severe symptoms (39.5% vs. 5.5%, P < 0.001) during reinfection. In multiple analysis, factors associated with an increased risk of severe symptomatic SARS-CoV-2 reinfection were increasing age (RR_{per year} = 1.007, 95% CI = 1.003-1.010), comorbidities (namely, obesity [RR = 1.12, 95% CI = 1.01-1.24], asthma [RR = 1.26, 95% CI = 1.06-1.50], type 2 diabetes mellitus [RR = 1.22, 95% CI = 1.07-1.38]), and previous severe laboratory-confirmed coronavirus disease 2019 (RR = 1.20, 95% CI = 1.03-1.39).

To the best of our knowledge, this is the first study evaluating disease outcomes in a large set of laboratory-positive cases of symptomatic SARS-CoV-2 reinfection, and factors associated with illness severity were characterized. Our results may contribute to the current knowledge of SARS-CoV-2 pathogenicity and to identify populations at increased risk of a poorer outcome after reinfection.