Investigation of descriptive characteristics of randomized controlled trials of COVID-19 vaccines

ABSTRACT

INTRODUCTION: The aim of this study was to examine the descriptive characteristics of randomized controlled trials published in PubMed on COVID-19 vaccines until May 30, 2021. METHODS: Seventy three articles reached by scanning the keywords "vaccine" and "COVID 19" in the PubMed database were reviewed by researchers, 33 randomized controlled trials (RCTs) related to COVID 19 vaccines were included in the study. According to the 17-item questionnaire created by the researchers, the descriptive features of included studies were examined. RESULTS: The total number of investigative authors in 33 RCT articles published in approximately one and a half years from the outbreak of the pandemic was 946, and the average number of authors per article was 28.67+or-18.56.39.3% of the articles were published in The Lancet and 27.2% in The New England Journal of Medicine. Of the vaccines used in the studies, 36.3% mRNA vaccine, 21.2% Inactivated vaccine, 18.1% Recombinant adenovirus vaccine, 12.1% Chimpanzee adenovirus-based vector vaccine, 6% BCG vaccine. 22.5% of vaccines are Phase 1, 12.9% Phase 2, 19.3% Phase 3, 3.2% Phase 4, 32.3% Phase 1-2, 9%,6 of them are Phase 2-3 studies. DISCUSSION AND CONCLUSION: The majority of randomized controlled trials on COVID-19 vaccines are phase 1 and phase 2 trials for mRNA vaccines and inactivated vaccines. Studies have generally been conducted on the adult age group and studies are needed to evaluate the effect of vaccines on the pediatric age group. In studies, the safety of vaccines has been examined more, and there is limited information on efficacy and effectiveness of vaccines.