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BCG vaccination and reduced morbidity and mortality for COVID-19 — non-peer reviewed US study

US researchers propose that the severity of COVID-19 impact may be linked to varying national policies on the childhood tuberculosis (TB) vaccine, Bacillus Calmette-Guerin (BCG). According to the WHO, BCG coverage in South Africa has remained between 80% and 90%, except in 2017 and 2018 when stock-outs hit the country and the rate dropped to 75% and 70% respectively.

The US currently leads the world in confirmed COVID-19 cases, followed by Italy, per the latest report from Johns Hopkins University’s Centre for Systems Science and Engineering (CSSE). Now NYITCOM researchers, led by Dr Gonzalo Otazu, assistant professor of biomedical sciences, propose that the severity of COVID-19 impact may be linked to varying national policies on BCG childhood vaccination.

“We found that countries without universal policies of BCG vaccination, such as Italy, the Netherlands, and the US have been more severely affected compared to countries with universal and long-standing BCG policies,” the researchers state.

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. 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 inoculation is also believed to offer broad-ranging protection against respiratory infections, which present similar symptoms to COVID-19.

In fact, Australian researchers have just announced plans to fast track large-scale testing to see if the BCG vaccination can protect health workers from the coronavirus.

The team compared various nations’ BCG vaccination policies with their COVID-19 morbidity and mortality and found a significant positive correlation between the year when universal BCG vaccination policies were adopted and the country’s mortality rate. In other words, the earlier a policy was established, the more likely that a significant portion of the population, especially the elderly, would be protected.

For example Iran, 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. In contrast, Japan, which started its universal BCG policy in 1947, has approximately 100 times fewer deaths per million people, with 0.28 deaths. Furthermore, Brazil started universal vaccination in 1920 and has an even lower mortality rate of 0.0573 deaths per million inhabitants.

So why do some nations vaccinate while others do not? As TB cases fell in the late 20th century, several higher-income countries in Europe dropped their universal BCG policies between 1963 and 2010. In the US, the CDC currently recommends the BCG vaccine only for very select persons who meet specific criteria and in consultation with a TB expert.

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.

Abstract
COVID-19 has spread to most countries in the world. Puzzlingly, the impact of the disease is different in different countries. 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 Bacillus Calmette-Guerin (BCG) childhood vaccination. 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. We also 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.

Authors
Aaron Miller, Mac Josh Reandelar, Kimberly Fasciglione, Violeta Roumenova, Yan Li, Gonzalo H Otazu

According to a report in The Times, the World Health Organisation (WHO) says more clinical trials are needed because it is important to know whether it is indeed the case that the BCG vaccine can reduce disease in those infected with the coronavirus. Bloomberg reports that the WHO is “encouraging international groups to collaborate with a study led by Nigel Curtis, head of infectious diseases research, at the Murdoch Children’s Research Institute in Melbourne, Australia”.

In that country, the vaccine (which is now about 100 years old) is being given to 4,000 health care workers to see if it will protect them. Similar research is going on in the Netherlands, and may also be rolled out in Boston and other Australian cities. “We wouldn’t be doing this if we didn’t think that this might work,” Curtis said. “We cannot guarantee that this will work. And of course, the only way to find out is with our trial.” Otazu and the team say that because the vaccine has reduced the number of reported cases in various countries, “BCG vaccination is a potential new tool in the fight against COVID-19”. The Times reports that according to the WHO, BCG coverage in South Africa has remained between 80% and 90%, except in 2017 and 2018 when stock-outs hit the country and the rate dropped to 75% and 70% respectively.

[link url="https://www.nyit.edu/box/features/tb_vaccine_could_be_a_valuable_weapon_in_covid_19_fight"]NYIT material[/link]

[link url="https://www.medrxiv.org/content/10.1101/2020.03.24.20042937v1"]MedRXiv abstract (not peer reviewed)[/link]

[link url="https://www.timeslive.co.za/news/south-africa/2020-04-03-can-sas-decades-old-vaccine-regime-work-in-our-favour-against-covid-19/"]Full report in The Times[/link]

See also

[link url="https://www.medicalbrief.co.za/archives/australia-fast-tracks-trial-of-bcg-vaccine-for-covid-19-on-4000-health-workers/"]Australia fast-tracks trial of BCG vaccine for COVID-19 on 4,000 health workers[/link]

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