Prevaccination Glucose Time in Range Correlates With Antibody Response to SARS-CoV-2 Vaccine in Type 1 Diabetes.

CONTEXT: Poor glucose control has been associated with increased mortality in COVID-19 patients with type 1 diabetes (T1D). OBJECTIVE: This work aimed to assess the effect of prevaccination glucose control on antibody response to the SARS-CoV-2 vaccine BNT162b2 in T1D. METHODS: We studied 26 patients with T1D scheduled to receive 2 doses, 21 days apart, of BNT162b2, followed prospectively for 6 months with regular evaluation of SARS-CoV-2 antibodies and glucose control. Immunoglobulin G (IgG) to spike glycoprotein were assessed by enzyme-linked immunosorbent assay, and serum neutralization by a live SARS-CoV-2 assay (Vero E6 cells system). Glycated hemoglobin A1c (HbA1c) and continuous glucose monitoring (CGM), including time in range (TIR) and above range (TAR), were collected. The primary exposure and outcome measures were prevaccination glucose control, and antibody response after vaccination, respectively. RESULTS: Prevaccination HbA1c was unrelated to postvaccine spike IgG (r = -0.33; P = .14). Of note, the CGM profile collected during the 2 weeks preceding BNT162b2 administration correlated with postvaccine IgG response (TIR: r = 0.75; P = .02; TAR: r = -0.81; P = .008). Patients meeting the recommended prevaccination glucose targets of TIR (≥ 70%) and TAR (≤ 25%) developed stronger neutralizing antibody titers (P < .0001 and P = .008, respectively), regardless of HbA1c. Glucose control along the study time frame was also associated with IgG response during follow-up (TIR: r = 0.93; P < .0001; TAR: r = -0.84; P < .0001). CONCLUSION: In T1D, glucose profile during the 2 weeks preceding vaccination is associated with stronger spike antibody binding and neutralization, highlighting a role for well-controlled blood glucose in vaccination efficacy.