Lower socioeconomic status strengthens the risk of otitis media with effusion after COVID-19 infection: a case-crossover study in Northeast China.

To investigate the associations of otitis media with effusion (OME) with different socioeconomic status (SES) before during and after the coronavirus disease 2019 (COVID-19) outbreak in Northeast China. Three cross-sectional data on daily emergency and outpatient were included pre, during and post COVID-19 epidemic. We recorded the number of OME and symptoms and confirmed SARS-Cov-2 infection in patients with OME. We used logistic regression to evaluate the odds ratio (OR) for OME with COVID-19 infection, and employed an interrupted time series analysis to quantify the effect of COVID-19 outbreak on OME, and a time-stratified case-crossover analysis to evaluate the association of OME with SES before, during and after the COVID-19 outbreak, especially in the two months following the COVID-19 outbreak. During COVID-19 outbreak, the OME significantly increased by 50% (RR: 1.563, 95% CI 1.256-1.942) compared to the same period in other years, low SES was associated with an increased risk of OME, but this low SES-related risk elevation significantly increased during the outbreak of COVID-19, especially in the first month after COVID-19 infection. Individuals under 50 years old were still vulnerable to SES after COVID-19 infection in Liaoning. Lower SES might aggravate OME and greater efforts are needed to improve SES in post-COVID-19.