He called the results of the type 1 diabetes study “very strong,” but urged caution, noting that other studies had disappointing results. A Dutch study of approximately 1,500 health professionals vaccinated with BCG found no reduction in Covid infections, and a South African study of 1,000 health professionals found no effect of BCG on the incidence or severity of Covid.
The results of BCG’s largest study, an international study that followed more than 10,000 health professionals in Australia, the Netherlands, the UK, Spain and Brazil, are still being analyzed and are expected in the coming months. The study also followed health professionals after they received Covid vaccines to see if BCG improved their responses.
“BCG is a controversial area — there are believers and non-believers,” said the lead researcher of that trial, Dr. Nigel Curtis, a professor of childhood infectious diseases at the University of Melbourne in Australia and leader of the Infectious Diseases Group at the Murdoch Children’s Research Institute. . (Dr. Curtis calls himself “an agnostic.”)
“Nobody is claiming there are off-target effects, but how profound is that and does it translate to a clinical effect? And is it limited to newborns, whose immune systems are more susceptible? These are very different questions,” said Dr. Curtis. .
A number of factors could explain the divergent findings. BCG is composed of a live attenuated virus that has been grown in labs around the world for decades and introduces mutations that cause different strains.
The lab of Dr. Faustman uses the Tokyo strain, which is considered particularly potent, said Dr. curtis. His own studies used the Denmark strain, which is the easiest to obtain. The number of doses can also have an effect on immunity, as many vaccines require repeated vaccinations to maximize protection.