The researchers found that in countries where many people received the vaccine, mortality from Covid-19 was lower.
While this does not mean that BCG somehow reduces the risk of serious illness from a coronavirus infection, it fits with other studies that suggest that BCG can generally strengthen people’s immunity and potentially help against the coronavirus.
The World Health Organization has warned against using the BCG vaccine against coronavirus until more is known, but teams around the world are looking into the possibility that this could help.
Luis Escobar from the Virginia Polytechnic Institute and colleagues used existing data to investigate whether countries without a national BCG vaccination program had higher coronavirus mortality rates. To enable a fair comparison, they considered factors such as population density, access to health care and response to Covid-1
“What sets our work apart is that we were very careful about removing variables,” said Carolina Barillas-Mury, a distinguished investigator at the National Institutes of Health who worked on the study. The association should have disappeared. Instead of disappearing, it got stronger – less complicated, “she told CNN.
Nonspecific vaccine immunity
The result is “remarkable but not enough to determine causality,” the team wrote. It is not enough to be sure that the BCG vaccine somehow protects people from coronavirus.
The BCG vaccine, which is over 100 years old, is used in many countries, including the United States, and is associated with reduced overall mortality in infants and children. There is strong evidence that the vaccine provides non-specific immunity protection beyond tuberculosis. The effects of the vaccine on adults have been inconsistent.
Other researchers have suggested that vaccines against polio and measles, mumps, and rubella could offer similar protection against fatal infections, including coronavirus.
Researchers warn that clinical trials are needed to demonstrate the vaccine’s effects on heavy Covid-19. Initial overseas clinical trials are currently focusing on healthcare workers at the forefront of the coronavirus battle.
A $ 10 million grant from the Bill and Melinda Gates Foundation in May supported clinical trials in Australia, Spain, and the Netherlands that will span 10,000 healthcare workers.
Dr. Denise Faustman, director of immunobiology at Massachusetts General Hospital and associate professor of medicine at Harvard Medical School, hopes to begin clinical trials with her team in Boston as soon as possible.
Faustman has been studying the side effects of the BCG vaccine for years. “BCG strengthens the innate immune system,” said Faustman. “So if you see an infectious disease, you can fight it faster.”
She says this is one of several recent studies that have confirmed the potential of the BCG vaccine as an instrument in the fight against coronavirus.
“The signal is really quite strong that countries with previous BCG vaccination are protected from incidence and mortality,” said Faustman, who added that there is even a possibility that the BCG vaccine may have the effectiveness of a coronavirus-specific vaccine after its use Manufacturing could increase.
If further testing confirms the protection of the BCG vaccine against the severity of the coronavirus could have a significant impact on public health.
Most Asian countries have universal BCG vaccination programs and the United States does not. According to the CDC, BCG is generally not recommended in the U.S. because the risk of infection is low, the effectiveness of the vaccine may vary, and may affect TB screening.
“It is possible that some of the social distancing strategies adopted by Asian countries to get their economies going again may not be effective in North America and Western European countries and may lead to a second wave of infections,” said Escobar’s team.
The vaccine could possibly be administered in countries where there is currently no universal vaccination program.
“The nice thing is that it is given only once. It may be feasible to increase vaccine production if it works and is safe,” said Dr. Wafaa El-Sadr, professor of epidemiology at Columbia University and director of the ICAP. a global health program.
Dr. William Schaffner, an infectious disease specialist at Vanderbilt University School of Medicine, who previously referred to the use of the BCG coronavirus vaccine as the “Hail Mary Pass”, warned against collecting too much inventory of observation data in different countries were collected since not all countries rate Covid-19 cases and deaths in the same way.
“It is certainly a novel and provocative approach to preventing this disease. We need all the help we can get,” said Schaffner, who agrees that clinical trials are needed to combat the effectiveness of the BCG vaccine Coronavirus really evaluate.
“What we saw is a preview of upcoming attractions, as it says in the cinema,” said Schaffner. “Let’s wait for the movie.”