BCG vaccine is safe, does not increase COVID risk: Study

The Bacille Calmette-Guerin or BCG vaccine, originally made against tuberculosis, has a general stimulating effect on the immune system and is therefore effective against COVID-19, say researchers.

The study, published in the journal Cell Reports Medicine, compared groups of volunteers who have received a BCG vaccine in the past five years (before the corona pandemic), showing that the vaccine is safe and possibly influences COVID-19 symptoms.

"It is very important to confirm that someone who has been vaccinated with BCG does not experience any increased symptoms during the COVID-19 pandemic," said study researcher Mihai Netea from Radboud University in the Netherlands.

The BCG vaccine is the most widely received vaccine in the world. Originally intended to treat tuberculosis, it later became apparent that it provides a long-lasting, general boost to the innate immune system.

The vaccine was therefore also effective against other conditions.

In the current study, the research team conducted research into these effects referred to as "trained immunity".

The '300BCG' study is a result of his work, in which a group of healthy volunteers received the BCG vaccine and could thus be compared to a group of healthy volunteers who did not.

Most volunteers received the vaccine between April 2017 and June 2018.

The purpose of that study was to determine the difference in the immune response, but now that the corona pandemic is present, the same subjects were questioned to see if there is an effect of the vaccine on the symptoms attributable to infection with the SARS-CoV-2 virus.

It's safe, perhaps a positive effect, the study showed.

What the comparison between the groups shows is that those who received the vaccine did not have more symptoms, did not get sick more often or become more seriously ill, during the first wave of the COVID-19 pandemic in the Netherlands.

The data show also a cautiously positive picture, with a lower number of sick people in the period March-May 2020 among the BCG-vaccinated group, and also a lower incidence of extreme fatigue among the vaccinated individuals.

The researchers underline that this was to be expected given the well-known effects of the BCG vaccine on healthy volunteers.

"Although we see less sickness in the people who have had the BCG vaccination, only the ongoing prospective BCG vaccination studies can determine whether this vaccination can help against COVID-19," Netea said.

Recently, another study published in the journal Science Advances, revealed that BCG vaccination can be effective in the fight against COVID-19.