Pacific islands immunization history may lower risk of coronavirus

APIA: Pacific islands may have lower cases of coronavirus due to a history of mandatory vaccine, namely the bacillus Calmette-Guerin (BCG) which is part of the immunization programme of many islands.

A study entitled ‘Correlation between universal BCG vaccination policy and reduced morbidity and mortality for COVID-19: an epidemiological study’ posted on medRxiv, finds a correlation between countries that require citizens BCG vaccine and those showing fewer number of confirmed cases and deaths from Covid-19.

“These differences are attributed to differences in cultural norms, mitigation efforts, and health infrastructure. Here we propose that national differences in COVID-19 impact could be partially explained by the different national policies respect to BCG childhood vaccination.”

The study notes that BCG vaccination has been reported to offer broad protection to respiratory infections. “We 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, Nederland, USA) have been more severely affected compared to countries with universal and long-standing BCG policies. Countries that have a late start of universal BCG policy (Iran, 1984) had high mortality, consistent with the idea that BCG protects the vaccinated elderly population,” the Authors wrote.

According to the research, they  found that BCG vaccination also reduced the number of reported COVID-19 cases in a country.

“The combination of reduced morbidity and mortality makes BCG vaccination a potential new tool in the fight against COVID-19.”

The study notes only a “correlation” and not a cause for the reduced numbers.

In Melbourne, Australia the B.C.G. vaccine was administered to thousands of physicians, nurses, respiratory therapists and other health care workers, as part of a randomized controlled trials intended to test the vaccine’s effectiveness against the coronavirus.

According to the World Health Organization BCG vaccine has existed for 80 years and is one of the most widely used of all current vaccines for infants in countries where it is part of the national childhood immunization programme. BCG vaccine has a documented protective effect against meningitis and disseminated tuberculosis in children.

Now B.C.G. is primarily used in the developing world and in countries where TB is still prevalent, where it is given to over 100 million babies a year.

According to WHO and UNICEF estimates of immunization coverage for Samoa, there was a notable decline in 2018 of BCG coverage.

BCG coverage for Samoa was reported at 62 % in 2018, according to the World Bank collection of development indicators, compiled from officially recognized sources. 

According to the authors of the study, Italy, the country with the highest number of deaths from COVID-19 with 13,915, has never universally applied tuberculosis vaccination. Japan, which has reported only 63 deaths from coronavirus and has taken less stringent containment measures, has a universal tuberculosis vaccination policy. The researchers also compared Iran to Japan, two countries that have applied universal BCG vaccination, but at different times. Japan started its universal BCG vaccination policy in 1947 while the Iranian policy was put in place in 1984. Japan has about 100 fewer deaths per million inhabitants than Iran, they found.

The Authors however suggest that it should only be viewed as a correlation.

“The correlation between the beginning of universal BCG vaccination and the protection against COVID-19 suggests that BCG might confer long-lasting protection against the current strain of coronavirus,” they said.

[Photo by Heilani Productions]

Link to the study: https://www.medrxiv.org/content/10.1101/2020.03.24.20042937v1

NYT Article: https://www.nytimes.com/2020/04/03/health/coronavirus-bcg-vaccine.html

TH Article: https://www.thehindu.com/sci-tech/health/coronavirus-correlation-does-not-mean-causation-say-doctors-about-bcg-vaccine-study/article31259472.ece

 

 

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s