1855-LB: Metformin Mitigates Insulin Signaling Variations Induced by COVID-19 Vaccine Boosters in Type 2 Diabetes

Objective: Diabetes is associated with an increased risk of coronavirus disease 2019 (COVID-19) morbidity and mortality. COVID-19 vaccines substantially reduce the risks of serious COVID-19 outcomes, but the impact of COVID-19 vaccines, including their effectiveness and adverse effects in patients with diabetes, is not well known.

Methods: Firstly, we used the mRNA COVID-19 vaccine to validate the effects of glucose control in mice after 4 dorse. Then, between 1 June 2023 and 31 October 2023, we recruited 176 adults who had received two doses of the mRNA COVID-19 vaccine (BNT162b2). The participants ranged in age from 18 to 65 years (median=53.5 years, interquartile range (IQR) 12.0), and (104/176)59.09% were male. Human volunteers were recruited to determine their immune responses and glucose control before and 2 weeks after the booster shot of the COVID-19 mRNA vaccine.

Results: We showed that four doses of the COVID-19 vaccine weekly could impair insulin sensitivity in healthy mice, and this effect can still be maintained after four weeks. Following that, we showed that 65/176 patients with type 2 diabetes exhibited aggravated insulin resistance toward booster shots of the COVID-19 vaccine after 2 weeks. We found that the aggravation of insulin resistance in patients with type 2 diabetes taking metformin was significantly lower than in patients not taking metformin after the booster shots of the COVID-19 vaccine.

Conclusion: This study suggests the clinical importance of close monitoring of glycemic control in diabetes after receiving COVID-19 vaccines and indicates the beneficial action of metformin, a common antidiabetic medication, in counteracting insulin signaling variations induced by COVID-19 vaccination in diabetes.