SARS-CoV-2 Reinfection Rate: A Systematic Review and Meta-analysis

Backgrounds: Reinfection among COVID-19 patients is still a challenging issue in the medical literature. Therefore, the current meta-analysis was conducted to estimate the pooled incidence rate of reinfection among COVID-19 patients. Materials Methods: A comprehensive search was conducted in PubMed, Web of Science, and Scopus databases from July 1 to October 1, 2021. Original studies which estimated the incidence rate of COVID-19 reinfection were included. CASP (Critical Appraisal skills program) was used to assess the quality of studies. Data were analyzed by STATA statistical software Version 15 (StataCorp, College Station, TX, USA). Findings: A total of 3803 articles were found, of which 16 articles remained after title, abstract, and full text screening. The minimum and maximum incidence rates of reinfection were 0.001 and 0.73%, respectively. The pooled estimated incidence rate of COVID-19 reinfection was 0.11% (95% confidence interval: 0.02-0.20, p .001, I2 = 100.0). The highest pooled estimated incidence rate of reinfection was observed in people 50 years old (0.14%) (95% CI: 0.001-0.34, p .001, I2 = 100). Regarding the time elapsed after the first infection, the highest reinfection rate occurred four months after the first infection (0.12%) (95% CI: 0.001-0.27, p .001, I2 = 100). Conclusion: The incidence rate of reinfection among COVID-19 patients is expected to be high. However, it seems that the influence of factors including the age of patients and the time elapsed after the first infection must be considered.