AUTHOR=Tang Xiujuan , Musa Salihu S. , Zhao Shi , He Daihai TITLE=Reinfection or Reactivation of Severe Acute Respiratory Syndrome Coronavirus 2: A Systematic Review JOURNAL=Frontiers in Public Health VOLUME=Volume 9 - 2021 YEAR=2021 URL=https://www.frontiersin.org/journals/public-health/articles/10.3389/fpubh.2021.663045 DOI=10.3389/fpubh.2021.663045 ISSN=2296-2565 ABSTRACT=As the pandemic continues, re-detectable positive (RP) SARS-CoV-2 viral RNA scenarios among recovered COVID-19 patients raised public health concerns recently. It is imperative to investigate whether a re-detectable positive (RP) SARS-CoV-2 scenario can cause severe infection to the vulnerable population. In this work, we conducted a systematic review of the literature to investigate reactivation and reinfection in recovered COVID-19 patients that were found positive for the second time after recovery. Our study, consisting of more than 113,715 number of recruited patients, indicates that the RP-SARS-CoV-2 scenario occurs plausibly due to reactivation, reinfection, viral shedding, or testing errors and might cause outbreaks. Nonetheless, we observe that previously infected individuals have a significantly lower risk of being infected for the second time, indicating that reactivation or reinfection of SARS-CoV-2 has a relatively minimal impact in the overall population than the primary infection.