Humoral immune response to COVID‐19 vaccination in diabetes is age‐dependent but independent of type of diabetes and glycaemic control: The prospective COVAC‐DM cohort study

AIMS: To investigate the seroconversion following first and second COVID‐19 vaccination in people with type 1 and type 2 diabetes in relation to glycaemic control prior to vaccination and to analyse the response in comparison to individuals without diabetes. MATERIALS AND METHODS: This prospective, multicentre cohort study analysed people with type 1 and type 2 diabetes and a glycated haemoglobin level ≤58 mmol/mol (7.5%) or >58 mmol/mol (7.5%), respectively, and healthy controls. Roche's Elecsys anti‐SARS‐CoV‐2 S immunoassay targeting the receptor‐binding domain was used to quantify anti‐spike protein antibodies 7 to 14 days after the first and 14 to 21 days after the second vaccination. RESULTS: A total of 86 healthy controls were enrolled in the study, as well as 161 participants with diabetes, of whom 150 (75 with type 1 diabetes and 75 with type 2 diabetes) were eligible for the analysis. After the first vaccination, only 52.7% of participants in the type 1 diabetes group and 48.0% of those in the type 2 diabetes group showed antibody levels above the cut‐off for positivity. Antibody levels after the second vaccination were similar in participants with type 1 diabetes, participants with type 2 diabetes and healthy controls after adjusting for age, sex and multiple testing (P > 0.05). Age (r = −0.45, P < 0.001) and glomerular filtration rate (r = 0.28, P = 0.001) were significantly associated with antibody response. CONCLUSIONS: Anti‐SARS‐CoV‐2 S receptor‐binding domain antibody levels after the second vaccination were comparable in healthy controls and in participants with type 1 and type 2 diabetes, irrespective of glycaemic control. Age and renal function correlated significantly with the extent of antibody levels.