U.S. scientists are investigating whether the Bacillus Calmette-Guerin (BCG) vaccine, administered to millions of Caribbean and Indian children soon after birth to protect against tuberculosis, could be a game-changer in the fight against the deadly COVID-19 strain of the coronavirus.
While developing a specific immunisation against the coronavirus sweeping the planet will likely take many months, researchers are studying the potential benefits of the BCG shot, which many people around the world receive as children.
Laboratories and pharmaceutical firms are racing to find medicines to tackle COVID-19, which has infected more than a million people, killed at least 50,000 and for which there is currently no known treatment, vaccine or cure.
The severity of COVID-19 impact may be linked to national policies on BCG childhood vaccination, the yet to be published study from the New York Institute of Technology (NYIT) states while citing the examples of Italy and the U.S.
"We have known for decades that BCG has non-specific beneficial effects", in that it protects against diseases other than the one for which it was created, Camille Locht, of the French public health research institute Inserm, told AFP.
Children vaccinated with BCG suffer less from other respiratory illnesses, it is used to treat certain bladder cancers and it could protect against asthma and autoimmune diseases such as type 1 diabetes.
“We found that countries without universal policies of BCG vaccination, such as Italy, the Netherlands, and the United States, have been more severely affected compared to countries with universal and long-standing BCG policies, noted the researchers led by Gonzalo Otazu, assistant professor of biomedical sciences at NYIT.
“While the U.S. has reported almost 1,90,000 cases with more than 4,000 deaths, Italy has 1,05,000 cases and over 12,000 fatalities. Netherlands has reported more than 12,000 cases of the disease and over 1,000 deaths,” says Medical Dialogues magazine.
According to the study, a combination of reduced morbidity and mortality could make the BCG vaccination a game-changer in the fight against COVID-19.
India, with the world's highest TB burden, introduced BCG mass immunisation in 1948. Indian experts said they were hopeful and encouraged but it was too early to say anything. Every small thing gives us a ray of hope. It will be premature to say anything now.
But the silver lining is that the BCG vaccine has proved quite effective against the SARS infection also, Monica Gulati, senior dean, Faculty of Applied Medical Sciences, Lovely Professional University (LPU), Punjab, said.
It was effective not in the sense that it was able to cure, but it was able to reduce the intensity, Ms. Gulati said. Ms. Gulati explained that the SARS virus is also basically a coronated virus. So since the current pandemic is less intense in the countries with BCG vaccine intervention and that it was effective against another coronavirus is reason for hope, she said.
Researchers want to test whether the tuberculosis vaccine could have a similar effect against the new coronavirus, either by reducing the risk of being infected, or by limiting the severity of the symptoms.
In France, where the BCG vaccine was compulsory until 2007, "most of the study participants will have already had a first vaccination", but the protective effect of this decreases over time, said Locht.
As one of the most widely used vaccines in the world, the BCG vaccine has existed for nearly a century and has been shown to be an effective tool in preventing meningitis and disseminated TB in children, the U.S. researchers said.
Iran, for instance, which has a current universal BCG vaccination policy that only started in 1984, has an elevated mortality rate with 19.7 deaths per million inhabitants, they said.
In contrast, Japan, which started its universal BCG policy in 1947, has approximately 100 times fewer deaths per million people, with 0.28 deaths, according to the study.
Brazil, which started universal vaccination in 1920 has an even lower mortality rate of 0.0573 deaths per million inhabitants, the scientists noted.
As TB cases fell in the late 20th century, several higher-income countries in Europe dropped their universal BCG policies between 1963 and 2010.
The researchers noted that among the 180 countries with BCG data available today, 157 countries currently recommend universal BCG vaccination. The remaining 23 countries have either stopped BCG vaccination due to a reduction in TB incidence or have traditionally favoured selective vaccination of at-risk groups, they said.
The BCG vaccine does not directly protect against the coronavirus, but provides a boost to the immune system which may lead to improved protection and a milder infection, Radboud university said of the study.
The idea is that the innate immune system can be prepared, or "trained" to better combat attacks, thanks in particular to live attenuated vaccines, such as BCG or measles, which contained a weakened sliver of the original pathogen.
In the case of COVID-19, in addition to infection by the virus itself, some patients have also suffered excessive immune responses, with the uncontrolled production of pro-inflammatory proteins, cytokines.
"Vaccination, in particular against BCG, might help to better orchestrate this inflammatory immune response," said Laurent Lagrost, Inserm research director who works on links between inflammation and the immune system.
The vaccine acts as a "military exercise in peacetime" so that the body can "fight the enemy effectively in wartime," he said in an interview this week with French broadcaster BFMTV.
Another advantage of the new vaccine is that it is made in Europe and could be quickly made available, while the BCG suffers from strong supply tensions and using it for adults against COVID-19 could deprive children of it in countries where tuberculosis remains endemic.
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