Effectiveness of COVID-19 Vaccines in Adults with Diabetes Mellitus: A Systematic Review

Abstract

Persons with diabetes mellitus may have an increased risk of severe illness or death from COVID-19 compared to persons without diabetes. Prior studies indicate that immune response and thus vaccine effectiveness might be lower in persons with diabetes. We aimed to systematically review the effectiveness of COVID-19 vaccines in adults with diabetes. Pubmed, Embase, Web of Science and Cochrane Library were searched for studies that evaluated the effectiveness of COVID-19 vaccines in adults with diabetes, published before 4 March 2022. Risk of bias in the included studies was evaluated using the ROBINS-I tool. At least two reviewers conducted the study selection, data extraction, and risk of bias assessment independently. After screening of 2196 studies, a total of 17 articles were included. Six different COVID-19 vaccines (Ad5-nCoV-S, AZD1222, BNT162b2, CoronaVac, JNJ-78436735, and mRNA-1273) were included in the synthesis. Vaccine effectiveness was reported for SARS-CoV-2 infection, symptomatic COVID-19, hospitalization, and death, and ranged from 24 to 96% in persons with diabetes, and from 33 to 97% in total study populations; effectiveness was generally lower for persons with diabetes. Odds ratios for breakthrough infection or severe COVID-19 ranged from 1.03 to 2.41 in vaccinated persons with diabetes compared to persons without diabetes. Even though the included studies were very heterogeneous, results from the synthesis indicate that effectiveness of COVID-19 vaccines might be lower in persons with diabetes. More research is needed on the comparison of vaccine effectiveness between persons with and without diabetes, and the effectiveness of repeat COVID-19 vaccinations.

Immune Response to CoronaVac and Its Safety in Patients with Type 2 Diabetes Compared with Healthcare Workers

“…Several previous studies conducted on COVID-19 vaccines’ immunogenicity and effectiveness in patients with diabetes compared to healthy controls. Most of these studies have reported lower vaccine effectiveness and immunogenicity in patients with diabetes when compared to healthy controls [ 27 , 28 ]. However, our study yielded different results, which could be attributed to various factors, such as the type of COVID-19 vaccine used, sample size, levels of glycaemic control and characteristics of the control group.…”

COVID-19 and metabolic syndrome

“…Immunogenicity of vaccines appear to be lower in people with diabetes irrespective of the type of vaccine and weaker with higher BMI and worse glucose control [49] . People with diabetes have relatively less protection against infection, hospitalization, severe disease and death [50] . However, these data are derived from observational studies with high risk of bias.…”

Diabetes, COVID‐19, and questions unsolved

“…A recent systematic review by van den Berg et al 119 -7 of 14 be performed due to the vast heterogeneity of the studies, vaccine effectiveness appeared to be generally lower in people with diabetes compared with the general population or people without diabetes.…”

“…Nevertheless, vaccination is still highly effective in this population, and no differences in mortality prevention have been observed. 119 It has come to light that poor glycaemic control may impair the immune response to vaccination. 115,121 Further studies are required to confirm this association; however, considering the existing evidence for poor glycaemic control compounding adverse outcomes COVID-19, careful monitoring and optimisation of glycaemic control is advised.…”

“…A recent systematic review by van den Berg et al 119 . focused on the clinical indicators of vaccine efficacy.…”