ABSTRACT
Objective: To evaluate the methodology of the published systematic reviews and Meta-analyses (SR/MA) on efficacy and safety of coronavirus disease 2019 (COVID-19) vaccines. Methods: We conducted a retrieval for literatures published as of December 10, 2021 in English databases (Medline, Embase, Cochrane Library, Web of science) and Chinese databases (CNKI, Wanfang data, VIP, Sinomed). Two reviewers independently screened literatures and extracted data. The methodology of included SR/MA papers was assessed by A MeaSurement Tool to Assess systematic Review-2 (AMSTAR-2) tool in 16 items. Results: A total 22 SR/MA papers were included, in which 3 (13.6%) had low quality and 19 (86.4%) had very low quality. The main problems of these SR/MA included having no definite PICO (Participants, intervention, control and outcome), providing no preliminary research protocol, no list of excluded studies and justify the exclusions, making no evaluation and explanation or discussion of the risk of bias of original studies, no adequate evaluation of publication bias and discuss its likely impact on the results, etc. Conclusion: SR/MA for the efficacy and safety of COVID-19 vaccines had varied methodological deficiencies, further improvements are needed.