Countries that have a widespread vaccination programme involving the Bacillus Calmette-Guérin (BCG) jab have a coronavirus death rate almost six times lower than nations that do not use it, a study reveals.
The BCG vaccine was invented a century ago and gives immunity to tuberculosis (TB) — a bacterial infection — but it is known to have other benefits.
Previous trials discovered people that receive the jab, which costs as little as £30, have improved immune systems and are able to protect themselves from infection.
For example, in a trial among Native Americans, BCG vaccination in childhood was able to offer protection against TB up to 60 years after vaccination.
The precise way this durable vaccine helps fend off other infections is relatively unknown but it may be by boosting the immune system’s innate mechanisms.
These so-called off-target effects include enhanced protection against respiratory diseases, and have been recognised by the World Health Organization (WHO).
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The Bacillus Calmette-Guérin (BCG) vaccine (pictured) is used to fend off tuberculosis (TB) but it has long been known to have other health benefits, including helping a person’s immune system to fend off respiratory infections
In the UK, all schoolchildren between ten and 14 were injected with the vaccine between 1953 and 2005.
As TB infection rates dropped, doctors abandoned mass vaccination and, in 2005, switched to targeting only the most at risk — such as babies with infected relatives.
Researchers hope it will turbo-charge the immune system so that it is in a heightened state of readiness and able to detect and destroy the virus before it wreaks havoc on the body.
The researchers adjusted for factors which can skew the findings, such as a nation’s wealth and the percentage of elderly people in its population.
They then looked at the mortality per one million residents of every country with sufficient data.
Researchers from the US write in their paper: ‘After adjusting for country economic status, proportion of older population and aligning the epidemic trajectories of the highest hit countries, the intriguing observation of a significant association between BCG use and lower COVID-19-attributable mortality remained discernable.’
The findings were published online on archive site medRxiv and not in a journal as the research has yet to be peer-reviewed — the process in which other academics scrutinise research.
The Johns Hopkins Bloomberg School of Public Health experts pooled publicly available data for the analysis.
An estimate on case fatality rate was produced from the best available data on mortality for the top 50 countries reporting highest case events.
‘In order to mitigate the bias centered around the differential epidemic time curves experienced by the different countries, we calculated days from the 100th COVID-19-positive case to align the countries on a more comparable time curve,’ the researchers explain.
The cases and deaths was then compared to vaccination programmes for the BCG vaccine.
Average death rate was also found to vary significantly according to a country’s economic classification.
COVID-19 mortality per one million for low-middle-income, upper-middle-income and high-income countries were 0.4, 0.65 and 5.5, respectively
Researchers call the fact the wealthier nations have a higher death rate ‘counter-intuitive’.
The BCG jab, which used to go to every child aged between ten to 14, was cut back in 2005 but Researchers hope it will turbo-charge the immune system so that it is in a heightened state of readiness and able to detect and destroy the virus before it wreaks havoc on the body
WHAT IS THE BCG VACCINE?
BCG is currently given to around 130 million babies every year to protect them from TB.
It has the full name ‘Bacillus Calmette-Guérin’ and featires a weekend version of the bacteria ycobacterium bovis.
This microbe causes TB in animals such as cows and badgers.
When injected into people, the weak bacteria is attacked by the immune system.
The body then defeats the bacteria by producing antibodies.
These can then be rapidly produced and deployed if a person is infected by TB proper.
The BCG jab is thought to work in this way but also revs up the whole immune system so it’s more likely to snuff out any invading virus particles.
The NHS says the BCG jab can offer protection for up to 60 years – but scientists are unclear if adults who were already injected as children get any protection from the coronavirus because the evidence is lacking.
The academics are unable to explain why that is but point to previous research which states ‘deaths from acute respiratory illness are typically higher in low-income settings due to multiple socio-demographic and economic risk factors’.
For example, COVID-19 is known to be more dangerous to people over the age of 65, and this demographic is less populous in poorer nations.
The researchers say their results should be taken with caution as there are several issues that may distort the findings.
‘[But] despite all these caveats, the inverse relationship between country economic status and COVID19-attributable mortality, and the strong ecological association with BCG vaccination are intriguing,’
‘The findings warrant deeper epidemiological scrutiny and prospective evaluation in individually randomized trials.’
Trials to asses the usefulness of the BCG vaccine in the fight against the coronavirus pandemic are already underway.
Lasts month, a trial started which includes 4,000 healthcare workers in Australia.
The trial will be led by Researchers at Melbourne’s Murdoch Children’s Research Institute and involve 4,000 health workers in various hospitals across the country.
Researchers hope administering the vaccine and boosting ‘innate immunity’ can buy enough time for specialised treatments and vaccines to be developed.