Own Correspondent|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 very little, 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).
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 Zimbabwe all schoolchildren between ten and 14 were injected with the vaccine for decades until recently.
As TB infection rates dropped, doctors abandoned mass vaccination and, 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’.
Source: Daily Mail – Articles