Risk and Protective Factors of Long COVID Incidence in the Borriana COVID-19 Cohort from 2020 to 2023: A Prospective Population-Based Cohort Study

Background and Objective: After a SARS-CoV-2 infection, a Long COVID (LC) syndrome occurred in a high proportion of patients with affecting their health. Estimating the incidence, risk and protective factors of LC was the aim of our study. Material and Methods: We performed a prospective population-based cohort study on the Borriana COVID-19 cohort (Castellon province, Valencia Community, Spain) from May 2020 to August 2023 with a follow-up of 40 months, and considering the LC definition from the World Health Organization. We used inverse probability weighted regression. Results: With a response rate of 63.8% of a total of 722 participants, the average age was 37.7±17.4 years with 460 (62.3%) females, 644 had suffered a SARS-CoV-2 infection, and 184 suffered LC with a cumulative incidence of 28.6%. A total of 135 patients with LC remained affected, and a death associated with the syndrome occurred in 0.54% of them. Significant risk factors for LC were older age, female, chronic disease, SARS-CoV-2 exposure, reinfections and severity. Asymptomatic cases and SARS-CoV-2 vaccinations were significantly protective factors. Conclusions: A high incidence of LC was found with low recovery rate, and several risk and protective factors. Continued follow-up for non-recovered LC patients, surveillance of infections, and a SARS-CoV-2 vaccination for an at-risk population can be recommended.