Vaccination and Younger Age Are Associated with Recurrent Laboratory-Confirmed Symptomatic SARS-Cov-2 Infections (preprint)

Background: Repeated SARS-CoV-2 infections are plausible and related published data are scarce. We aimed to identify factors associated with the risk of recurrent (three episodes) laboratory-confirmed symptomatic SARS-CoV-2 infections. Methods: A retrospective cohort study was conducted and 1,700 healthcare workers were enrolled. We used risk ratios (RR) and 95% confidence intervals (CI) to evaluate factors associated with symptomatic SARS-CoV-2 infections. Results: We identified 14 participants with recurrent illness episodes. Therefore, the incidence rate was 8.5 per 10,000 person-months. In multiple model, vaccinated adults (vs. unvaccinated, RR = 1.05 [1.03 - 1.06]) and those with a severe first illness episode (vs mild disease, RR = 1.05 [1.01 - 1.10]) were at increased risk for repeated symptomatic SARS-CoV-2 reinfections. Increasing age showed a protective effect (per each additional year of age: RR = 0.98 [0.97 - 0.99]). Conclusions: Our results suggest that recurrent SARS-CoV-2 infections are rare events in adults and they seem to be determined, partially, by vaccination status and age.

Male gender and kidney illness associated with an increased risk of severe laboratory-confirmed coronavirus disease (preprint)

ObjectiveTo identify factors predicting severe coronavirus disease 2019 (COVID-19) in adolescent and adult patients with laboratory-positive (quantitative reverse-transcription polymerase chain reaction) infection. MethodsA retrospective cohort study took place, and data from 740 subjects, from all 32 states of Mexico, were analyzed. The association between the studied factors and severe (dyspnea requiring hospital admission) COVID-19 was evaluated through risk ratios (RRs) and 95% confidence intervals (CIs). ResultsSevere illness was documented in 28% of participants. In multiple analysis, male gender (RR = 1.13, 95% CI 1.06 - 1.20), advanced age ([reference: 15 - 29 years old] 30 - 44, RR = 1.02, 95% CI 0.94 - 1.11; 45 - 59, RR = 1.26, 95% CI 1.15 - 1.38; 60 years or older, RR = 1.44, 95% CI 1.29 - 1.60), chronic kidney disease (RR = 1.31, 95% CI 1.04 - 1.64) and thoracic pain (RR = 1.16, 95% CI 1.10 - 1.24) were associated with an increased risk of severe disease. ConclusionsTo the best of our knowledge, this is the first study evaluating predictors of COVID-19 severity in a large subset of the Latin-American population. It is also the first in documenting gender-related differences regarding the severity of the illness. These results may be useful for health care protocols for the early detection and management of COVID-19 patients that may benefit from opportune and specialized supportive medical treatment.