Patients with type 2 diabetes mellitus present similar immunological response to COVID-19 BNT162b2 mRNA vaccine to healthy subjects: a prospective cohort study

Aim To compare the kinetics of neutralizing antibodies (NΑbs) against SARS-CoV-2 after vaccination with the BNT162b2 mRNA vaccine (Comirnaty, Pfizer/BioNTech) between patients with T2DM and healthy controls. Methods NAb levels after the BNT162b2 mRNA vaccine were compared between 50 patients with non-insulin treated T2DM and 50 age-, gender-, and BMI-matched healthy controls up to 3 months after the second dose. The median age of both groups was 70 years. Results On day 1, mean NAbs of the control and T2DM groups were 14.64% (standard error, SE = 2.30) and 14.04% (SE = 2.14), respectively ( p value = 0.926). Three weeks later, the mean NAb values were 39.98% (SE = 3.53) in the control group and 40.97% (SE = 3.99) in participants with T2DM ( p value = 0.698). One month after the second vaccination, mean NAb values increased to 87.13% (SE = 2.94) in the control group and 89.00% (SE = 2.18) in the T2DM group. Three months after the second vaccine dose, the mean inhibitory titers decreased to 83.49% (SE = 3.82) (control group) and 76.36% (SE = 3.33) (T2DM group). On all occasions, no significant difference was found between the two groups (all p values > 0.05). Conclusions Patients with T2DM present similar immunological response to COVID-19 BNT162b2 mRNA vaccine to that of healthy subjects.