BCG vaccine appears to protect patients with type 1 diabetes from COVID-19 infection

Multiple does of the Bacillus Calmette-Guerin (BCG) vaccine appears to offer patients with type 1 diabetes strong protection against COVID-19, researchers reported on August 15, 2022 in Cell Reports.

“Multiple studies have shown that adults with type 1 diabetes who are diagnosed with COVID-19 are at increased risk of severe illness,” said lead Denise Faustman, MD, PhD, director of the Immunobiology Laboratory at Massachusetts General Hospital in Boston. “We found that three doses of BCG administered prior to the start of the pandemic prevented infection and limited severe symptoms from COVID-19 and other infectious diseases.”

As background, the authors noted that the BCG vaccine is an avirulent tuberculosis strain Mycobacterium bovis usually administered as prophylaxis against tuberculosis. It has been the most widely administered vaccine in medical history.

The subjects in the COVID trial had previously been enrolled in a trial testing the efficacy of BCG vaccine against a variety of infections among persons with type 1 diabetes.

Subjects had received multiple BCG vaccinations prior to the onset of the pandemic in early 2020. With the onset of COVID, the investigators added COVID to the group of diseases for which the BCG vaccine was being tested.

There were 144 adult type 1 diabetics (96 BGC treated and 48 placebo treated) enrolled in the COVID-19 trial. They were followed for COVID-19 related outcomes for 15 months.

“During this time period of this trial, other COVID-19 vaccines were not yet available and therefore had no influence on this study,” the authors noted.

There were no drop-outs over the 15-month trial.

The investigators reported that 12.5% of placebo-treated and 1% of BCG-treated subjects developed confirmed COVID-19, with an efficacy for BRG vaccination of 92%.

“The BCG group also displays fewer infectious disease symptoms and lesser severity, and fewer infectious disease events per patient, including COVID-19,” the researchers said.

The investigators reported no BCG-related systemic adverse events.

The authors concluded, “BCG’s broad-based infection protection suggests that it may provide platform protection against new SARS-CoV-2 variants and other pathogens.”