Abstract
BACKGROUND: In Autumn 2022, a surge in upper respiratory tract infections (URTIs) was observed worldwide. Individuals anecdotally reported increased URTIs in the months following their coronavirus disease 2019 (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 health care workers (HCWs) from Montreal, Canada. HCWs completed biweekly surveys to report incident COVID-like symptoms. We included HCWs actively followed up for ≥90 days, between December 1, 2021, and December 31, 2022. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections were confirmed via reverse transcriptase polymerase chain reaction/antigenic testing. Non-COVID-19 URTI cases were defined as new onset of fever/sensation of fever, rhinitis, nasal congestion, sore throat/pharyngitis, sneezing, coughing, wheezing, 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 HCWs (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 (hazard ratio, 1.03; 95% CI, 0.74-1.43; P = .87). However, having at least 1 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.