Tuberculosis vaccine tested on Dutch elderly in fight against corona

Scientists are going to investigate whether a tuberculosis vaccine protects vulnerable elderly people when they become infected with the coronavirus. This week, 22 hospitals will start research on some 6,000 vulnerable elderly people. They will also investigate whether the vaccine has an effect on other respiratory tract infections.

Immediate cause for the research is a study that appeared in the journal Cell on Monday. In it, 198 Greek elderly were given the so-called BCG vaccine or a placebo a few years ago when they were discharged from hospital.

“A year later, the elderly who received the vaccine had experienced 40 percent fewer infections and 80 percent fewer respiratory tract infections than those who received a placebo,” says Mihai Netea, Professor of Experimental Internal Medicine at Radboudumc. “The vaccine strengthens the innate immune system and we think this effect will last for about three to five years. Whether it also protects against Covid-19 has yet to be determined.”

“Strictly speaking, we don’t know whether the vaccine protects against the coronavirus,” responds Marjolein van Egmond, professor of immunology at the Amsterdam UMC. “But I see no reason to think it wouldn’t work. So far the new coronavirus has behaved in terms of immune response just like other respiratory viruses”

Cรฉcile van Els, professor of vaccinology at Utrecht University and affiliated with the RIVM, is more cautious. “We must beware of false expectations. At the moment there is no evidence that the BCG vaccine protects people against covid-19 and we should not use means that have not been proven effective outside scientific research”

Nevertheless, Van Els is also positive about the research that is now starting. “We often see the innate immune system as a system that can’t learn anything, but you can stimulate it to grow more muscle. This allows you to react a little faster to pathogens. So it’s good to investigate this thoroughly for covid-19.”

If the tuberculosis vaccine does indeed arm vulnerable elderly people against the coronavirus, it can offer extra protection until there is a vaccine that specifically prevents this coronavirus, thinks Marc Bonten, the doctor-microbiologist who coordinates the research at the UMC Utrecht. “And if that covid-19 vaccine will eventually be available, then it still makes sense to know whether the tuberculosis vaccine protects vulnerable elderly people against other respiratory tract infections

Vulnerable elderly

The vulnerable elderly taking part in the research will be recruited via the hospitals. People over the age of sixty who are discharged from the hospital or who have a chronic disorder and come in for a check-up can participate. Half of the participants get the tuberculosis vaccine, the other half get a placebo.

Bonten hopes that the investigation will be completed before 1 January. Whether or not the tuberculosis vaccine will indeed protect vulnerable elderly people against covid-19 is still uncertain. That largely depends on how many people become infected with the virus in the autumn. “This is precisely why we are also looking at other respiratory tract infections,” says Bonten.

The research that is now starting is not the first study in the Netherlands into the effect of the tuberculosis vaccine against covid-19. In March a study was started among about 1500 care workers and in April a study among 1600 healthy elderly people. Internationally there are about fifteen studies, estimates Netea of the Radboudumc.

“These studies are still ongoing. It is not yet possible to draw any conclusions because fortunately fewer people were infected than expected,” says Netea. “As a result, we can’t yet see any major differences between the groups. By focusing on so many participants now, we hope for quicker results” The more people take part, the higher the chance that there are participants with the coronavirus who can see what the vaccine does.

Advice on vaccine postponed

Whether the tuberculosis vaccine will ultimately be administered on a large scale in the Netherlands depends on the Health Council of the Netherlands’ advice. Earlier this year, VWS asked the Council to advise on the supply of the vaccine.

The advisory report was due to be published at the end of next week, but a spokesman for the Health Council of the Netherlands says it has been postponed until the end of September. “A number of recent studies are still under review.” The council is also aware of the article in Cell. The new study in vulnerable elderly people will therefore not be awaited.