Researchers have been studying the effects of a very old vaccine still being used in many countries for tuberculosis (TB) disease, BCG. It is mostly given to children to prevent tuberculosis, a bacterial infection of the lungs that can lead to death. TB can also infect other areas of the body such as the brain and bone.
The BCG vaccine was being researched due to its ability to stimulate immune responses against other types of bugs—not just tuberculosis, which is a bacteria. Some studies show it can stimulate protection against viruses and parasites.
Children vaccinated with the BCG vaccine in Spain have a much lower rate of ANY infection leading to hospitalization. This is compared to children without the vaccine.
The BCG vaccine is a live vaccine and comes from different stocks of tuberculosis bacteria. Different research studies were using different forms. Some of these forms are not as effective as others.
What did studies show?
Some of these studies came up with quite different results. One studied the rate of COVID infections in diabetic patients. The rate of COVID infection for BCG vaccinated diabetic patients was only about 1% while the unvaccinated group was 12%! This study only had a few hundred patients but did use the stronger form of the bacteria in the vaccine.
Other studies of healthcare workers didn’t show any effect. This may be due to different reasons. A different form of the bacteria may have been used in their BCG vaccine. It was also not known when they last had the vaccine or how many doses they had. In comparison, the diabetes study patients had recently had 3 doses of the BCG vaccine.
This all looks very promising for a vaccine that might be able to fight a variety of diseases. It stimulates an overall immune response instead of targeting the specific bug. This allows this same vaccine to work for 100s of years because it doesn’t matter what the bug’s mutations are.
Consider our current situation with the COVID-19 vaccine. It is no longer as effective against the COVID virus due to mutations. If we could use a well-known vaccine that works with any age and is well tolerated that could be a game changer!
BCG vaccine protection from severe coronavirus disease 2020, Proceedings of the National Academy of the Sciences of the United States of America website, PNAS, accessed August 2022
BCG vaccination to reduce the impact of COVID-19 in healthcare workers: Protocol for a randomized controlled trial (BRACE trial) 2021 October 28, Pubmed website, National Library of Medicine, accessed August 2022
Multiple BCG vaccinations for the prevention of COVID-19 and other infectious diseases in Type-I Diabetes 15 August 2022, Cell Report Medicine website, A Cell Press Journal, accessed August 2022.