Study finds diabetes worsened by COVID-19 and its vaccines

A new study suggests COVID-19 and the vaccines against it have something in common: both can make diabetes worse.

A study by Lixiang Zhai and 11 co-authors, first posted in pre-print December 27 2023, found negative effects of mRNA COVID vaccines on people who are diabetic or prediabetic.

“Diabetes is associated with an increased risk of Coronavirus disease 2019 (COVID-19) vulnerability and mortality,” the authors note.

“Here, we showed that 61.1% of patients with type 2 diabetes, but not healthy controls, exhibited aggravated insulin resistance towards the booster shots of the COVID-19 vaccine.”

Data for the study Metformin mitigates insulin signaling variations induced by COVID-19 vaccine boosters in type 2 diabetes was collected in the middle of last year.

“Between 1 June 2023 and 31 October 2023, we recruited 155 adults who have received two doses of the mRNA COVID-19 vaccine (BNT162b2). The participants ranged in age from 18 to 65 years (median=53.5 years, IQR 12.0) and 60.25% are male. Human volunteers were recruited to determine their immune responses and glucose control before and two weeks after the booster,” the authors explained.

“About 61.1% of diabetic subjects had impairment of insulin sensitivity according to the HOMA-IR index and about 66.7% of diabetic subjects had increased risks of cardiovascular complications according to the TyG index.”

The authors said a correlation analysis showed the spike proteins that result from the COVID-19 vaccine boosters impair glucose control and insulin resistance.

The researchers also injected mice with the vaccine once a week for five weeks and found parallel problems.

“Interestingly, we showed mice after the fourth dose of COVID-19 vaccine exhibited impaired glucose tolerance examined by oral glucose tolerance test. Serum insulin level or bodyweight, is significantly elevated in mice with weekly COVID-19 vaccination, indicating an increased risk of cardiovascular diseases and metabolic disorders,” the authors explained.

“The glucose intolerance induced by the COVID-19 vaccine is mediated by impairment of insulin sensitivity rather than impaired insulin secretion in mice.”

Diabetes increases the chances of contracting COVID-19, which in turn makes diabetes worse, the authors noted.

A study of the electronic medical data of 3,102 prediabetic people in the Bronx, New York, published in BMJ found that patients with a history of COVID-19 had a significantly higher risk of developing type-two diabetes within one year of infection compared to other vaccine recipients. A systematic review published in BMC Medicine in November 2022 reached similar conclusions.

Zhai and co-authors said the SARS-CoV-2 spike protein “may persist even after several months of the COVID-19 vaccination” giving even more time to lead to type-2 diabetes. The spike protein may lead to insulin resistance and impaired glucose metabolism and “may directly affect insulin signaling via binding toll-like receptor (TLR4) and estrogen receptor (ER) which is involved in the regulation of insulin signaling, which may lead to reduced insulin secretion and insulin resistance."

“Second, the SARS-CoV-2 spike protein induced by the COVID-19 vaccine is known to cause systemic immune responses and the production of IgG antibodies of the SARS-CoV-2 spike protein by the host, which may affect the function of insulin signaling pathways and lead to insulin resistance.”

On Substack, mathematician Igor Chudov, an unvaccinated prediabetic whose blood sugar levels relapsed to unhealthy after COVID-19, expressed gratitude to the researchers.

“I would like to compliment the authors, who bravely showed the deleterious effect of COVID-19 vaccines, something for which their careers will probably suffer, and also found out what exactly is the culprit in the COVID-19 vaccine,” Chudov wrote.

“I feel very sorry for those mRNA-vaccinated mice. Is their risk of ‘dying suddenly’ increased? It sure looks like it!”

Chudov said he embraced a vegan diet for the past four weeks and it seemed to help his blood sugars. Still, he ended his post on a cynical note.

“The takeaway is that both COVID-19 vaccines and COVID-19 make diabetes worse. For that, we need to thank the inventors of COVID, as well as the creators of COVID vaccines - who happen to be mostly the same people,” he quipped.