New vaccine blocks Covid-19, variants, other Coronaviruses

New York, May 11

US researchers have developed a potential new vaccine, which has proven effective against the original SARS-CoV-1, SARS-CoV-2 as well as its UK, South Africa and Brazil variants and related bat Coronaviruses that could potentially cause the next pandemic.

The new vaccine, called pan-coronavirus vaccine, was found effective in protecting monkeys and mice.

Pan-coronavirus vaccine triggers neutralising antibodies via a nanoparticle. The nanoparticle is composed of the Coronavirus part that allows it to bind to the body's cell receptors and is formulated with a chemical booster called an adjuvant. Success in primates is highly relevant to humans, said researchers from the Duke University in North Carolina, US.

The findings, published in the journal Nature, showed that the nanoparticle vaccine, in monkeys, blocked Covid-19 infection by 100 per cent. The new vaccine also elicited significantly higher neutralising levels in the animals than current vaccine platforms or natural infection in humans.

"We began this work last spring with the understanding that, like all viruses, mutations would occur in the SARS-CoV-2 virus, which causes Covid-19," said senior author Barton F Haynes, director of the Duke Human Vaccine Institute (DHVI).

"The mRNA vaccines were already under development, so we were looking for ways to sustain their efficacy once those variants appeared.

"This approach not only provided protection against SARS-CoV-2, but the antibodies induced by the vaccine also neutralised variants of concern that originated in the UK, South Africa and Brazil. And the induced antibodies reacted with quite a large panel of coronaviruses," Haynes said.

The team built on earlier studies involving SARS, the respiratory illness caused by a coronavirus called SARS-CoV-1. They found a person who had been infected with SARS developed antibodies capable of neutralising multiple coronaviruses, suggesting that a pan-coronavirus might be possible.

They identified one particular receptor-binding domain site that is present on SARS-CoV-2, its circulating variants and SARS-related bat viruses that makes them highly vulnerable to cross-neutralising antibodies.

The team then designed a nanoparticle displaying this vulnerable spot. The nanoparticle is combined with a small molecule adjuvant, which boosts the body's immune response to fight the disease.

IANS