medwireNews: Poor glycemic control is associated with an impaired immune response to vaccination against SARS-CoV-2 and an increased risk for breakthrough infections in people with type 2 diabetes, report researchers.
The findings suggest “that this specific aspect of diabetes management might contribute to the success of the vaccination programme,” write Antonio Ceriello (IRCCS MultiMedica, Milan, Italy) and study co-authors in Nature Communications.
“In addition, they might further suggest to consider patients with poorly controlled diabetes as a high-risk group to be prioritized for booster doses of vaccine.”
The team looked at immune responses in 494 people with type 2 diabetes from the Campania region of Italy at each of five clinic visits over 1 year, starting from 14 days after they had received their second dose of the Pfizer–BioNTech (BNT162b2) vaccine.
Of these study participants, 196 had good glycemic control, defined as a 1-year average glycated hemoglobin (HbA1c) level below 7% (53 mmol/mol), and this group had significantly better immune responses to immunization than the other 298 people, who had poor glycemic control.
At 1 year after immunization, the average neutralizing antibody capacity as a percentage of neutralization was over 50% in people with good glycemic control, but only about 20% in those with poor control.
Likewise, the proportion of T cells producing interferon-γ, interleukin-2, and tumor necrosis factor-α in people with good control was more than double that in people with poor control. In line with this, the 1-year average HbA1c level significantly correlated with all these measures of immune response.
During follow-up averaging 346 days, 3.6% of the people with good glycemic control had a PCR-confirmed SARS-CoV-2 infection, as did 10.5% of those with poor control. This amounted to a significant 74% reduction in infection risk after accounting for age, sex, BMI, diabetes duration, high-density lipoprotein cholesterol, cardiovascular risk factors, and medications.
Furthermore, average HbA1c significantly correlated with the risk for breakthrough infections. The only other factors to significantly increase this risk were smoking and male sex.
Ceriello also presented the results at the ATTD conference in Barcelona, Spain, where he speculated that delaying vaccine administration in people with type 2 diabetes until good glucose control is achieved might “emphasize the effect of the vaccination.”
He said that controlled studies would be necessary to test this and suggested that forthcoming vaccines against recent SARS-CoV-2 variants may provide the opportunity.
medwireNews is an independent medical news service provided by Springer Healthcare Ltd. © 2022 Springer Healthcare Ltd, part of the Springer Nature Group
29 April 2022: The coronavirus pandemic is affecting all healthcare professionals across the globe. Medicine Matters’ focus, in this difficult time, is the dissemination of the latest data to support you in your research and clinical practice, based on the scientific literature. We will update the information we provide on the site, as the data are published. However, please refer to your own professional and governmental guidelines for the latest guidance in your own country.