Researchers at Massachusetts General Hospital (MGH) have published a new paper in Medicine Cell Reports Demonstrating the protective ability of multiple doses of Bacillus Calmette-Guerin (BCG) vaccine against COVID-19 and other infectious diseases.
In a double-blind, placebo-controlled study of type 1 diabetes conducted at the start of the epidemic (before COVID-19 vaccines became available), researchers found that 12.5% of the placebo-treated subjects and 1% of the BCG-treated individuals met the criteria for confirmed COVID-19. , yielding a vaccine efficacy of 92%.
The group vaccinated against BCG also showed protective effects against other infectious diseases, including fewer symptoms, lower severity, and fewer infectious disease events per patient. No systemic adverse events related to BCG occurred.
Extensive protection from infection with BCG suggests that, in addition to COVID-19, it may provide protection against novel SARS-CoV-2 variants and other pathogens.
The researchers hope the findings will prompt a larger study of the effects of the BCG vaccine in type 1 diabetics, who are among the most vulnerable to COVID-19.
The BCG vaccine is one of the spoiled strains of tuberculosis Mycobacterium bovis It is historically given to protect against tuberculosis, and since its introduction in 1921, it has been the most widely used vaccine in the history of medicine.
BCG is considered extremely safe, is on the World Health Organization’s List of Essential Medicines and is given to nearly 100 million children annually worldwide. BCG is also one of the most affordable drugs, costing less than a dollar per dose in many parts of the world.
“Multiple studies have shown that adults with type 1 diabetes who have been diagnosed with COVID-19 are at an increased risk of developing serious illness.
We found that three doses of BCG vaccine prior to the start of the pandemic prevented infection and limited severe symptoms of COVID-19 and other infectious diseases.
Unlike the antigen-specific vaccines currently used to prevent COVID-19, the mechanism of action of BCG is not limited to a specific virus or infection,” says Denise Faustman, MD, director of the Immunobiology Laboratory at Massachusetts General Hospital.
Participants in the COVID trial had previously enrolled in a clinical trial to test the efficacy of the BCG vaccine for type 1 diabetes. Participants in the test group received multiple vaccines before the outbreak of the epidemic in early 2020.
“This data set is unique and exciting because all patients had been 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 a previous BCG vaccine. This eliminates the major confounding factors that other limited trials have.”
The results support the idea that BCG needs time to have a clinical effect, but its effects may be very permanent and lasting,” says Hazel Dockrell, the London School of Hygiene and Tropical Medicine, an expert in infectious diseases who was not formally involved in the study.
The 144 adult diabetic patients (96 BGC treated and 48 placebo) analyzed in the COVID-19 trial were part of a phase 2 ongoing clinical trial testing BCG as a treatment for adults with type 1 diabetes. Patients were followed up for COVID-19-related outcomes for 15 months.
Outcomes of the COVID-19 trial included: rate of COVID-19 infection, symptoms associated with COVID-19, reduction in overall contagious disease, and presence and densities of SARS-CoV-2 antibody level. Type 1 diabetes outcomes were not unblinded as part of this study and will be unblinded upon completion of the trial in 2023.