US study links fewer coronavirus deaths to TB vaccine; Indian doctors say more research needed to draw any conclusion
With a new study linking BCG vaccination with scale of severity of COVID-19 globally, doctors in India said "large-scale epidemiological studies" need to be conducted before drawing any conclusion.
According to the study led by a US-based researcher, a combination of reduced morbidity and mortality could make the Bacillus Calmette-Guerin (BCG) vaccination a "game-changer" in the fight against novel coronavirus.
The BCG vaccine is part of India''s universal immunisation programme and administered to millions of children at birth or soon after it.
Arvind Kumar, lung surgeon at the Sir Ganga Ram Hospital said, while there seems to be an apparent link between BCG vaccination and COVID-19 cases reported in various countries, it will be "premature" to say there is a direct correlation.
"Large-scale epidemiological studies need to be conducted before we can draw any conclusion on this link, as suggested by the study," he told PTI.
The lung surgeon conjectured that as far as India and its demography is concerned, there is a possibility that "we have developed a better immune system to this virus through prior infections" which people in the western countries may not have been exposed too.
"Besides, their are other confounding factors like lockdown imposed in India by the government when the infection was in stage 2. And there is a possibility that a less virulent strain of COVID-19 is in circulation in India," Kumar said.
India, with the world''s highest TB burden, introduced BCG mass immunisation in 1948.
Ravi Shekhar Jha, Senior Consultant and head of the pulmonology department, Fortis Escorts, Faridabad, echoed Kumar''s views.
"This is too early to say there is a direct link. Unless we do rigorous and large-scale epidemiological studies, we can''t say anything conclusive in this perceive correlation as put out in the study," he said.
The yet to be published study from the New York Institute of Technology (NYIT) states while citing the examples of Italy and the US that the severity of COVID-19 impact may be linked to national policies on BCG childhood vaccination.
"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 US has reported almost 1,90,000 cases with more than 4,000 deaths, Italy has 1,05,000 cases and over 12,000 fatalities. The Netherlands has reported more than 12,000 cases of the disease and over 1,000 deaths.
Jha of Fortis hospital, however, said the lockdown can only slow down the number of cases of infection but mortality as such will not be affected much.
So, the BCG-COVID link needs to be further investigated and any direct correlation being attributed at this time would be too far-fetched, he said.
Rommel Tickoo, associate Director, internal medicine, Max healthcare, also pitched for large-scale epidemiological studies to further probe this link, if any.
Australia and other countries which plan to hold trials for this vaccine on health workers will be able to see the difference, if seen, he said.
In Iran too, the age-group born after 1984 when the vaccination was started there, the intensity of cases in that segment is different compared to those before it, the doctor said, adding that Indians may have developed a better immunity to coronavirus due to other previous infections.
So, large-scale trials are needed before one draws any conclusion, Tickoo added.
Updated Date: Apr 02, 2020 21:57:31 IST
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