Background: Diabetes mellitus (DM) could hamper the immune responses, including that induced by the vaccine. The aim of this study was to evaluate the immunogenicity of coronavirus disease 2019 (COVID-19-19) inactivated vaccines in patients with DM either controlled or uncontrolled through a systematic review approach.
Methods: Without regard to time constraints, searches were conducted in ProQuest, Embase, and PubMed to assess the available data on the impact of DM regulation on the immunogenicity of post-vaccinated DM patients. The PRISMA guideline and the PICO criteria were used. The quality of studies was assessed using the National Institutes of Health (NIH) quality assessment tool. There is not enough Available data comparing the immunogenicity of the vaccine in controlled and uncontrolled DM patients is limited.
Results: Out of 20,657 articles, five studies were included, of which three had good quality and two had fair quality. Our data suggested that DM patients vaccinated with CoronaVac/SinoVac had lower seroconversion rates significantly lower compared to non-DM patients. The immunogenicity of BBV-152 vaccine in DM patients was also significantly lower than in patients without DM. Studies comparing the immunogenicity of the vaccine between controlled and uncontrolled DM patients are limited.
Conclusion: Patients with DM have lower antibody levels than non-DM patients who received inactivated COVID-19 patients. Glycemic management has emerged as critical to maximizing the immunogenicity induced by inactivated vaccines in a small number of patients; however, to support this conclusion, studies with adequate number of patients are critical.