- With the poliovirus virtually eradicated, we barely think about the polio vaccine anymore
- Research from the 1950s, however, resurfaced as sons of renowned virologists remember how this vaccine protected them from other illnesses
- A novel vaccine would still be best, but existing vaccines can plug the gap
As the Covid-19 pandemic progresses, researchers are focusing their efforts on finding a dedicated vaccine or treatment. Without a vaccine, there is nothing else to do but to impose measures such as face masks and physical distancing to curb infections.
But, as a shortcut, many medical professionals have wondered about the efficacy of existing vaccines. The tuberculosis vaccine, for example, was one of them. Now, the sons of the couple who did research on a polio vaccine in the 1950s, wondered if this could not be used in the fight against the novel coronavirus.
Lack of respiratory infections in those who have had polio vaccine
According to a feature published by the New York Times, the sons of Dr Marina Voroshilova, a virologist during the 1950s, also grew up to become virologists – and posed the question whether the live polio vaccine could be relevant during the Covid-19 pandemic.
The reason? People who received this vaccine never became sick with other viral illnesses for at least a month afterwards. Dr Voroshilova injected her boys with the polio vaccine each fall to protect them against seasonal influenza.
With this observation, scientists in various countries are wondering if this vaccine couldn’t be repurposed as a temporary protection measure against the SARS-CoV-2 virus. Polio has been practically eradicated around the globe, but could this welcome benefit help us during the current pandemic?
What is the polio vaccine?
According to the World Health Organization, the polio vaccine contains a mixture of weakened polioviruses of three serotypes, which all have been selected to mimic the immune response when the body is infected with the poliovirus, but not to the extent that it can spread to the central nervous system and cause illness.
An American, Dr Jonas Salk, developed the first polio vaccine, which consisted of a completely inactivated virus. In 1955, the vaccine was widely introduced. Dr Albert Sabin, however, tested a vaccine using a live, yet weakened strain, but at the time, authorities were not sure whether this “live virus” would be safe.
Dr Sabin then passed these three strains on to a married pair of virologists, Dr Mikhail Chumakov and Dr Voroshilova, who experimented with this vaccine on their sons. Clinical trials then started taking place and the oral vaccination was officially put in use from 1961 onwards.
But does it work for other illnesses?
According to the New York Times, the Soviet Union did further studies from 1968 to 1975 and found that this oral polio vaccine did reduce deaths from seasonal influenza.
Right now, Dr Peter Chumakov, son of Dr Mikhail Chumakov, is taking the polio vaccine which he grew in his own laboratory as a possible precaution against Covid-19.
But what do experts think about this? Just like with the repurposing of other existing vaccines and medication, they do suggest that it is done with extreme caution.
“We are much better off with a vaccine that induces specific immunity,” Dr Paul A Offit, a co-inventor of a vaccine against the rotavirus and professor at the Perelman School of Medicine at the University of Pennsylvania, told the New York Times. Any benefits from a repurposed vaccine, he said, are “much shorter-lived and incomplete”, as opposed to a vaccine specifically created for a virus.
Although the polio vaccine has been so effective that polio has become basically non-existent, there is the slightest possibility that the weakened virus can mutate into a stronger form and make people sick – even though the chances are extremely slim.
Repurposing existing vaccines is not a novel idea. Dr Robert Gallo, the director of the Institute of Human Virology at the University of Maryland School of Medicine stated that even the smallest time frame of immunity from an existing vaccine can bridge the gap between now and when a targeted vaccine is finally rolled out on a mass scale.
Trials for the polio vaccine used against SARS-CoV-2 are now underway in Russia according to reports, and research papers are being published to discuss this possibility.
And what about the promises of the TB vaccine?
Health24 reported on the possibility of repurposing the tuberculosis vaccine in April 2020. We spoke to Dr Johnny Peter, Head of the Division of Allergology and Clinical Immunology at Groote Schuur Hospital, University of Cape Town. According to Peter, it is true that the BCG vaccine may offer a broad spectrum base immunological benefit against a host of respiratory infections, but it’s simply not enough to rely on a vaccine we received at birth.
Currently, there are more than 125 vaccine developments happening around the world as scientists race towards the ultimate SARS-CoV-2 vaccine, with several in clinical trial stage.
READ | 6 things you need to know about the first SA Covid-19 vaccine trial
READ | Could the TB vaccine you received at birth help protect against the coronavirus? We asked an expert
Image credit: Chogniti Khongchum from Pexels