1486-P: Effects of the COVID-19 Booster Vaccine on Glycemia and Insulin Resistance in People with Type 1 Diabetes—A Prospective Pilot Study

Background: Inflammation is well-known to worsen glycemia in people with type 1 diabetes (T1D). COVID-19 vaccines are vital for protection against SARS-CoV-2 infection, but by necessity trigger an acute immune response. Case reports have described hyperglycemic crises shortly after a booster dose. However, effects of COVID-19 vaccines on glycemic control in T1D is poorly understood. Methods: This was a prospective cohort study of adults with T1D receiving a COVID-19 booster dose. At the baseline visit a blinded Dexcom G6 Pro CGM was placed, subjects received COVID-19 booster vaccine 3-4 days later, and returned 6 days post-vaccination to have the CGM removed. Primary outcome was change in mean daily glucose level from baseline. Secondary outcomes included total daily insulin dose (TDI), total daily insulin resistance (TDIR = mean glucose * TDI), and time in range (TIR = %glucose readings between 70-180mg/dL). Data were transformed as necessary to maintain normality. Results: We enrolled 20 adults with T1D; one subject was excluded for nonadherence with study procedures. Baseline characteristics included (mean±SD) age: 48.9±19.4y, sex: 68.4%F, BMI: 29.6±6.2kg/m2, A1c: 7.0±1.0%. 42% received a Moderna and 58% Pfizer-BioNTech booster. Mean glucose on Day#2 post-vaccination was significantly greater than baseline (165.1±27.4 vs 154.5±30.2 mg/dL, p=0.04), as was TDIR (7970±4113 vs 7036±3999; p=0.02). No other days had significant differences in glycemic metrics as compared to baseline. There were no differences in any outcome metrics between booster vaccine manufacturers. Conclusions: These results suggest that adults with T1D may experience transient glycemic elevations after receiving a COVID-19 booster. Clinicians may need to warn people with T1D to be more vigilant with glucose testing and insulin dosing temporarily after vaccination. Larger studies are warranted to corroborate these findings. Disclosure M.Zilbermint: Consultant; EMD Serono, Other Relationship; American Association of Clinical Endocrinologists. M.Motevalli: None. K.Batty: None. J.Venner-walcott: None. A.Edwards: None. T.Burley: None. K.Jackson: None. M.Akhtar: None. A.Demidowich: Research Support; Dexcom, Inc. Funding Dexcom, Inc. (IIS-2021-136)