Association of vaccine status, reinfections, and risk factors with Long COVID syndrome

The COVID-19 pandemic had a profound global impact, characterized by a high fatality rate and the emergence of enduring consequences known as Long COVID. Our study sought to determine the prevalence of Long COVID syndrome within a population of Northeastern Mexico, correlating it with patients' comorbidities, number of COVID-19 reinfection, and vaccination status. Employing an observational cross-sectional approach, we administered a comprehensive questionnaire covering medical history, demographics, vaccination status, COVID-related symptoms, and treatment. Our participant cohort included 807 patients, with an average age of 41.5 (SD 13.6) years, and women accounting 59.3% of the cohort. The follow-up was 488 (IQR 456) days. One hundred sixty-eight subjects (20.9%) met Long COVID criteria. Long COVID-19 was more prevalent when subjects had reinfections (p = 0.02) and less frequent when they had a complete vaccination scheme (p = 0.05). Through logistic regression, we found that male gender (OR 0.5, p ≤ 0.001), blood types of AB- (OR 0.48, p = 0.003) and O- (OR 0.27, p ≤ 0.001) in comparison with A+ and two doses of vaccines (OR 0.5, p = 006) to be protective factors against Long COVID; while higher BMI (OR 1.04, p = 0.005) was a risk factor. We saw that the prevalence of Long COVID was different within vaccinated patients and specific blood types, while being female and a higher BMI were associated with an increased risk of having long-COVID.