Multiple doses of the tuberculosis vaccine help to protect people with type 1 diabetes from COVID-19, researchers have said.
They are calling for wider studies into the effectiveness of the Bacillus Calmette-Guerin (BCG) vaccine after their study found that it also reduced the number and severity of the symptoms of other infectious diseases.
The study, which was carried out at the start of the pandemic and prior to the release of any COVID-19 vaccines, involved 144 adults with type 1 diabetes.
Ninety-six people were administered with the BCG vaccine, while 48 were given a placebo. The team from Massachusetts General Hospital said the vaccine’s effectiveness proved to be 92%.
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Dr Denise Faustman, director of the Immunobiology Laboratory at Massachusetts General Hospital, said: “Multiple studies have shown that adults with type 1 diabetes who are diagnosed with COVID-19 are at increased risk of severe illness.
“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.
“Unlike the antigen-specific vaccines currently in use to prevent COVID-19, BCG’s mechanism of action is not limited to a specific virus or infection.”
The BCG vaccine was introduced in 1921 to protect against tuberculosis and has been the most widely used vaccine in medicine, being given to around 100 million children every year around the world.
Hazel Dockrell, an infectious diseases expert from the London School of Hygiene & Tropical Medicine, described the findings from the latest study – which she was not involved with – as “exciting”.
She said: “This data set is unique and exciting because the patients were all vaccinated with multiple doses of BCG prior to the onset of the epidemic. Prior to the trial they had no known exposure to tuberculosis or prior BCG vaccination. This eliminates the major confounding factors that have limited other trials.
“The results support the idea that BCG needs time to have a clinical effect, but its effects may then be very lasting and durable.”
The study has been published in the journal Cell Reports Medicine.
