Century-old vaccine protects type 1 diabetics from infectious diseases

Key Takeaways

• New research shows that the 100-year-old Bacillus Calmette-Guérin (BCG) vaccine, originally developed to prevent tuberculosis, protects individuals with type 1 diabetes from severe COVID-19 disease and other infectious diseases.
• The BCG vaccine offers the prospect of near-lifelong protection against every variant of COVID-19, the flu, respiratory syncytial virus, and other infectious diseases for people with type 1 diabetes.

In new research, investigators at Massachusetts General Hospital (MGH) show that the 100-year-old Bacillus Calmette-Guérin (BCG) vaccine, originally developed to prevent tuberculosis, protects individuals with type 1 diabetes from severe COVID-19 disease and other infectious diseases. Two back-to-back clinical trials found that the BCG vaccine provided continuous protection for nearly the entire COVID-19 pandemic in the US, regardless of the viral variant. Results of the trials were published in Cell Reports Medicine andiScience.

“Individuals with type 1 diabetes are highly susceptible to infectious diseases and had worse outcomes when they were infected with the SARS-CoV-2 virus,” said senior author Denise Faustman, MD, PhD.  “Published data from other investigators show mRNA COVID-19 vaccines are not very effective in this group of vulnerable patients. But we’ve shown that BCG can protect type 1 diabetics from COVID-19 and other infectious diseases.”

The MGH trials enrolled 141 participants with type 1 diabetes; 93 people in the treatment group received five or six doses of BCG vaccine and 48 individuals in the placebo group received sham vaccine. All patients were followed for 36 months to capture diverse COVID-19 genetic variants and many infectious disease exposures. During the earlier Phase II trial (January 2020 to April 2021) when the virus was more lethal but less transmissible, the BCG vaccine’s efficacy was 92%, comparable to the efficacy of the Pfizer and Moderna COVID-19 vaccines in healthy adults. Over the full 34 months of the US COVID-19 pandemic, the BCG vaccine had a significant efficacy of 54.3%. In contrast, the investigators observed that the Pfizer, Moderna, and Johnson & Johnson vaccines did not protect people with type 1 diabetes against COVID-19. The investigators also found that the BCG-treated participants had lower rates of viral, bacterial, and fungal infections as well as COVID-19 disease.

The BCG vaccine confers an immunity that likely lasts decades, a clear advantage to the COVID-19 vaccine and vaccines against other infectious diseases, such as influenza, where the duration of effectiveness is only two or three months. Faustman said, “As the pandemic continues to evolve it will be interesting to see if we can work with the FDA to allow access to BCG vaccine for type 1 diabetics, who appear to be particularly at risk for all infectious diseases.”

Edited by Miriam Kaplan, PhD

Source: Massachusetts General Hospital, ScienceDaily, May 23, 2024; see source article