Is COVID-19 Associated with an Increased Risk of Subsequent Upper Respiratory Tract Infections in Adults? A Prospective Cohort Study

Background In Autumn 2022, a surge in upper respiratory tract infections (URTI) was observed worldwide. Individuals anecdotally reported increased URTI in the months following their COVID-19. The objective was to assess if COVID-19 is associated with a higher incidence of URTI in adults in the following months. Methods “RECOVER” is a prospective cohort of healthcare workers (HCW), from Montreal, Canada. HCW completed biweekly surveys, to report incident COVID-like symptoms. We included HCW actively followed-up for ≥90 days, between December 1st, 2021, and December 31st, 2022. SARS-CoV-2 infections were confirmed via RT-PCR/antigenic testing. Non-COVID-19 URTI cases were defined as new onset of fever/sensation of fever, rhinitis, nasal congestion, sore throat/pharyngitis, sneezing, cough, wheeze, difficulty breathing, increased respiratory secretions, or change in characteristics of chronic secretions, excluding symptoms within 48 hours of vaccination. Time-dependent Cox regression was used to assess the association between recent COVID-19 and URTI, adjusting for sex, age, workplace, household children <5 years, and asthma. Results Among 320 HCW (82.5% females, mean age 42.4 years), followed for a median of 342 days, 152 (47.5%) participants tested positive for SARS-CoV-2. No significant difference in the incidence of URTI was observed following COVID-19 (HR: 1.03; 95% CI, 0.74-1.43; P=.87). However, having at least one child <5 years was associated with a 74% (95% CI, 20-153%; P=.003) increase in the risk for URTI. Findings remained similar in sensitivity analysis. Conclusions There was no association between COVID-19 and subsequent URTI. Other epidemiological, individual and social factors could explain the increase in the incidence of URTI.