systematic review (SR) is defined as “a summary of research that addresses a focus clinical question in a systematic, reproducible manner” (Murad et al., 2015). Often, SR is accompanied by a so-called meta-analysis (MA), which refers to statistical pooling or combining of the results from different studies on the same topic (Lee, 2018; Murad et al., 2015). The advantages of MAs over the narrative summary of evidence are well-known. For example, MAs are able to yield a single best estimate of effect which could facilitate clinical decision-making (Murad et al., 2015). In addition, MAs narrow the confidence interval (CIs) (increases precision) by bring together individual primary studies (Lee, 2018). The scientific value and importance of MAs have been widely recognized and accepted among researchers and clinicians, and therefore the conduct of MAs is increasingly popular. The high popularity of MAs can be seen in the synthesis of evidence regarding COVID-19. As of September 15, 2021, a search in PubMed with the keywords “COVID-19” and ‘meta-analysis” in the title field with the filter “meta-analysis” yielded over...