covid-19 reinfection rate and related risk factors in fars province, iran: a retrospective cohort study

Background: reinfection with coronavirus diseases 2019 (covid-19) has raised remarkable public health concerns globally. therefore, the present retrospective cohort study intended to investigate covid-19 reinfection in registered patients of fars province in iran from february 2020 to april 2021.methods: the patients’ data, including the covid-19 infection, symptoms, comorbidities, and demographics, were collected using the health information systems (hiss). the patients were divided into three groups in terms of the duration between the initial infection and reinfection, including 28-44, 45-89, and more than 90 days. following the univariate analysis, logistic regression was used to investigate the factors effective on covid-19 reinfection. results: a total of 213768 patients had a positive polymerase chain reaction (pcr) test. the reinfection rate was 0.97% (2079 patients). of these re-infected individuals, 14.9%, 18.5%, and 66.6% had their second positive test 28-45, 45-89, and ≥90 days later, respectively. the mean duration between the initial infection and reinfection was 130.56 days (29-370 days). the chance of reinfection was significantly higher in the youths (odds ratio (or)=2.055; p<0.001), men (or=1.283; p<0.001), urban population (or=1.313; p<0.001), and healthcare providers (or=4.453; p<0.001). the patients with chronic pulmonary diseases, chronic kidney diseases, and malignancy were 1.421 (p=0.036), 2.239 (p<0.001), and 3.437 (p<0.001) times, respectively, more likely prone to reinfection. conclusion: the results of this study showed that there is a higher risk of reinfection in several vulnerable groups including healthcare providers, young individuals, residents of urban areas, men, and individuals with underlying diseases.