Document Type : Letter to Editor
Coronavirus disease (COVID-19) is an ongoing global pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Many systematic reviews and meta-analyses discussed the correlation of COVID-19 with a different disease. Given the urgent need for data, some meta-analyses containing datasets included many manuscripts, but their providence was not clearly reported. The possible overlap between some of the studies included in the analyses is a significant issue for conducting systematic reviews during the COVID-19 pandemic.