Researchers have found that tuberculosis (TB) vaccine, Bacillus Calmette-Guerin (BCG), could potentially serve as a new tool in the battle against the deadly coronavirus after analysing how COVID-19 has affected different countries.
The study posited that the differences in the manner in which the infection has impacted different nations could partially be illustrated by the national policies different nations have with regards to childhood BCG vaccination. The study was made available on medRxiv, a pre-print repository.
One of the most widely used vaccines
The BCG vaccine has existed for almost a century and is one of the most widely used of all current vaccines. BCG vaccine has a documented protective effect against meningitis and disseminated TB in children.
It has also been reported to offer broad protection to respiratory infections. For the study, the researchers compared large number of countries BCG vaccination policies with the morbidity and mortality for COVID-19.
"We found that countries without universal policies of BCG vaccination (Italy, the Netherlands, the US) have been more severely affected compared to countries with universal and long-standing BCG policies," said the study conducted by researchers from New York Institute of Technology (NYIT) College of Osteopathic Medicine in the US.
Study found a correlation between COVID-19 and vaccination policy
The number of confirmed coronavirus cases in the US has increased to 142,502, the highest in terms of infections globally, according to the latest tally from Johns Hopkins University's Center for Systems Science and Engineering (CSSE).
The CSSE data showed that at least 34,026 people have died due to the disease in the country. In Italy, which is one of the worst affected countries, 10,779 people have died due to COVID-19. In this latest study on impact of BCG vaccination on COVID-19, researchers also found that countries that have a late start of universal BCG policy, for example, Iran had high mortality, consistent with the idea that BCG protects the vaccinated elderly population.
"There was a positive significant correlation between the year of the establishment of universal BCG vaccination and the mortality rate, consistent with the idea that the earlier that a policy was established, the larger fraction of the elderly population would be protected," said the study.
"For instance, Iran has a current universal BCG vaccination policy but it just started in 1984, and has an elevated mortality with 19.7 deaths per million inhabitants. "In contrast, Japan started its universal BCG policy in 1947 and has around 100 times less deaths per million people, with 0.28 deaths. Brazil started universal vaccination in 1920 and also has an even lower mortality rate of 0.0573 deaths per million inhabitants," the result showed.
BCG vaccination a new potential tool
Iran announced 2,901 new COVID-19 cases on Sunday as the total number of confirmed cases soared to 38,309. Also, the death toll from the disease reached 2,640 in Iran, while 12,391 patients have recovered.
As the numbers of tuberculosis cases dropped in the late 20th century, several middle-high and high-income countries in Europe dropped the universal BCG policy between the years 1963 and 2010.
"The combination of reduced morbidity and mortality makes BCG vaccination a potential new tool in the fight against COVID-19," the researchers concluded. Gonzalo H. Otazu of NYIT is the corresponding author of the study. The COVID-19 death toll in Europe climbed to over 21,000 out of more than 360,000 confirmed cases.
(With inputs from agencies)