A vaccine that has been in use for almost a century limits the spread and severity of coronavirus, Israeli biologists have claimed after studying data from almost two thirds of the world’s population.
As they champion the bacillus Calmette-Guerin vaccine, they are going head-to-head with the World Health Organization. They argue that three decades after many countries — Israel included — phased out blanket BCG shots, they should consider restoring them to fight the pandemic.
“We found that countries with more coverage of BCG in the last 15 years have better outcomes for coronavirus — better death rates and fewer people being infected,” Nadav Rappoport, a Ben-Gurion University of the Negev computational biologist, told The Times of Israel.
The BCG shot, primarily used to fight tuberculosis, was first given to humans 99 years ago, in July 1921. While the researchers say BCG is not a substitute for a vaccine against COVID-19, they do argue that data shows BCG coverage contributes to the “attenuation of the spread and severity of the COVID-19 pandemic.”
Co-author Michal Linial of the Hebrew University said that while the WHO has strongly opposed deploying the vaccine against the virus, her team thinks countries that don’t use the BCG should consider doing so immediately. “There’s nothing to lose but a lot to gain,” she said.
Rappoport, together with Linial and two other Hebrew University biologists, crunched data on BCG use alongside coronavirus incidence and morbidity in 55 countries, home to 62.9 percent of the world’s population.
Their work adds to a growing body of international research examining whether BCG has benefits in fighting the coronavirus, including a new University of Michigan study that “suggests that mandated BCG vaccination can be effective in the fight against COVID-19.”
The Israel researchers also tested to see whether there was a correlation between the coronavirus and another common vaccine, against measles and rubella, and found that there wasn’t.
Linial told The Times of Israel that their results were starkest when looking at some neighboring countries that are divided by BCG policy.
The UK, which ended widespread BCG vaccination in 2005, ranks third in the world in terms of coronavirus deaths per million people, while Ireland, where it was given until 2015, ranks 17th. Spain ranks 6th, and ended blanket vaccination in 1981, while Portugal gave the BCG vaccine until 2017, and ranked 33rd. The United States has not given widespread BCG vaccinations, and ranks 10th.
“Portugal has a long border with Spain, which did really badly and has another wave now, but Portugal, with poor economics and health care, is doing much better,” said Linial. “And take the UK and Ireland — the difference in coronavirus is huge.”
The World Health Organization has rejected deployment of BCG to reduce the impact of the coronavirus, writing: “There is no evidence that the Bacille Calmette-Guérin vaccine (BCG) protects people against infection with COVID-19 virus.”
The WHO went on to argue: “In the absence of evidence, WHO does not recommend BCG vaccination for the prevention of COVID-19.”
And some doctors reject the view that there is nothing to lose by administering the vaccine. The Indian Council of Medical Research plans to give the vaccine to some elderly people. “This worries me a lot,” tweeted Dr. Madhukar Pai, director of the McGill International TB Centre at McGill University in Montreal, Canada.
He argued: “Millions of infants get BCG every year. It is quite safe in this group. But the number of elderly people given BCG is close to zero. BCG is a live vaccine. It should not be given to elderly (who might have co-morbidities) without safety data.”
The WHO is waiting for clinical trials that examine whether recently vaccinated people fare better against coronavirus. But Rapaport’s team argued that trials based on individuals won’t fully show the benefits of the vaccine, which are best discerned on countrywide levels.
Linial said: “I would start giving the BCG vaccination more widely now — it’s very safe, with very long experience.” She argued: “If it were an experimental vaccine I would be extremely worried but with this vaccine there are more than 90 years of experience and billions of people have received it.”
Linial acknowledged that her research is statistical and doesn’t prove a cause-and-effect relationship between BCG and reduced impact of coronavirus, or explain the science of why the vaccine may help. Nevertheless, she said, the figures point to strong trends that are too important to be ignored.
The Israeli researchers found that BCG correlation was significant among those aged 24 and younger who had received the vaccination in the last 15 years. Among older adults who got the BCG vaccine years ago, there was no discernible correlation between BCG rates and coronavirus infection.
Scientists have been discussing the potential of BCG since early in the pandemic. In the US, the National Institutes of Health (NIH) cautiously reported in June that their statistics “suggest that BCG could have a protective effect,” stressing that clinical trials are needed to find out more.
Now, some trials are underway, including one in the US involving 1,800 people and another in Australia involving 10,000 healthcare workers. Participants are being given BCG and scientists are monitoring whether being newly vaccinated with it makes them less likely than others to catch the coronavirus, and better equipped to fight it if they are infected.
The NIH researchers cautioned that correlations between BCG and the coronavirus are “difficult to validate due to broad differences between countries such as socioeconomic status, demographic structure, rural versus urban settings, time of arrival of the pandemic, and the number of diagnostic tests and criteria for testing.”
Rappoport said that his team tried to overcome such challenges by adjusting figures to account for demographic, economic, pandemic-restriction-related and health-related country-based variables, and also for different start dates of the health crisis in different countries.
Original: Nathan Jeffay – TOI