COVID-19 boosters associated with transient increases in glycemia, study finds
A small cohort study of patients with type 1 diabetes who received COVID-19 booster vaccines found significant increases in their blood glucose levels on the second and third day after vaccination.
Patients with type 1 diabetes may have a transient elevation in blood glucose levels after a COVID-19 booster vaccine, according to a small new study.
The prospective cohort study included 21 adults with type 1 diabetes who wore blinded continuous glucose monitors for 10 days (mean age, 47.4 years; 62% female; average HbA1c level, 6.9%). After a baseline period, all participants received an mRNA COVID-19 booster vaccine (8 Moderna, 13 Pfizer-BioNTech). Results of the study, which was funded by an investigator-initiated grant from DexCom, Inc., were published by Diabetes Research and Clinical Practice on Sept. 5.
None of the glycemic measures significantly changed overall, but participants' mean daily glucose level was significantly increased compared to baseline (162.9 mg/dL [9.04 mmol/L]) on day 2 (172.8 mg/dL [9.59 mmol/L]) and day 3 (173.1 mg/dL [9.61 mmol/L]) after vaccination. Glucose excursions were more common on vaccination day and day 1, but not to a statistically significant level. The participant with the most profound glycemic excursion had increases in glucose levels of 36%, 69%, 35%, 26%, 22%, and 19% on days 0 to 5, respectively, compared to baseline. Insulin resistance was also increased overall on day 2 (P=0.03). The outcomes did not vary significantly by patient sex or age or vaccine manufacturer.
“These results suggest that adults with type 1 diabetes may experience transient mild glycemic elevations after receiving a COVID-19 booster vaccination,” concluded the study authors. They noted that the results “are congruent with the scant literature” examining this question with other vaccines and called for additional research on that topic. In the meantime, clinicians may want to counsel patients with type 1 diabetes to be more vigilant with glucose testing and insulin dosing for the first five days after COVID-19 vaccination, the authors recommended.