Scientists have made a “promising” advance towards developing a universal coronavirus vaccine to tackle Covid-19 and the common cold.
Researchers at the Francis Crick Institute in London have discovered that a specific area of the spike protein of Sars-CoV-2 – the virus that causes Covid-19 – is a good target for a pan-coronavirus jab that could offer protection against all the Covid-19 variants and common colds.
Developing a vaccine that protects against a number of different coronaviruses is a huge challenge, they said, because this family of viruses have many key differences, frequently mutate and generally induce incomplete protection against reinfection. That is why people can repeatedly catch common colds, and why it is possible to be infected multiple times with different variants of Sars-CoV-2.
A universal coronavirus vaccine would need to trigger antibodies that recognise and neutralise a range of coronaviruses, scientists said, stopping the virus from entering hosts cells and replicating.
In the new study, the researchers investigated whether antibodies targeting the “S2 subunit” of Sars-CoV-2’s spike protein also neutralise other coronaviruses. The researchers found that after vaccinating mice with Sars-CoV-2 S2, the mice created antibodies able to neutralise a number of other animal and human coronaviruses.
They included the common cold coronavirus HCoV-OC43, the original strain of Sars-CoV-2, the D614G mutant that dominated in the first wave, Alpha, Beta, Delta, the original Omicron and two bat coronaviruses. The findings are published in the journal Science Translational Medicine.
“The S2 area of the spike protein is a promising target for a potential pan-coronavirus vaccine because this area is much more similar across different coronaviruses than the S1 area,” said the study’s co-first author, Kevin Ng, of the Francis Crick Institute. “It is less subject to mutations, and so a vaccine targeted at this area should be more robust.”
Until now, the S2 area of the spike protein had been overlooked as a potential basis for vaccination, the researchers said.
George Kassiotis, corresponding author and principal group leader at the Francis Crick Institute, said: “The expectation for a vaccine that targets the S2 area is that it could offer some protection against all current, as well as future, coronaviruses.
“This differs from vaccines that target the more variable S1 area which, while effective against the matching variant they are designed against, are less able to target other variants or a broad range of coronaviruses.
“There’s a lot of research still to do as we continue to test S2 antibodies against different coronaviruses and look for the most appropriate route to design and test a potential vaccine.”
The researchers will continue their work studying the potential of a pan-coronavirus that targets the S2 area of the spike protein and how it could be integrated with currently licensed vaccines.
Nikhil Faulkner, a co-first author, also of the Francis Crick Institute, said: “While a potential S2 vaccine would not stop people being infected, the idea is it would prime their immune system to respond to a future coronavirus infection.
“This would hopefully provide enough protection to survive an initial infection during which they could develop further immunity specific to that particular virus.”
Prof Penny Ward, a visiting professor in pharmaceutical medicine at King’s College London, who was not involved in the study, said a universal coronavirus vaccine “could solve the problem of endless new waves of disease caused by variants with reduced vaccine sensitivity”.