Research provides hope for ‘Holy Grail’ coronavirus vaccine

A Singapore-based study has fuelled hopes that a vaccine might one day offer protection against a range of different coronaviruses – and not just the SARS-CoV-2 virus that dominates now.
 
The research, published last week in the New England Journal of Medicine, tracked the post COVID-vaccine antibody responses of people who had previously been exposed to the 2002–04 severe acute respiratory syndrome (SARS) outbreak.
 
While the small-scale study only measured the reactions of eight Singaporean SARS survivors, the findings were striking. Participants showed a ‘potent’ and far broader immune response to related coronaviruses than was recorded in other control groups, including those already exposed to COVID-19.
 
Professor Bruce Thompson, the Dean of the School of Health Sciences at Swinburne University, described the findings as ‘pretty exciting’.
 
‘What these guys have done is smart,’ he told newsGP. ‘It’s a very interesting idea. When I read it, I thought “this is like Barry Marshall”.
 
‘What they’ve done is thought “let’s just go back to our lab book and have a look at SARS-CoV-1 and see what we can find here”.
 
‘It’s very early days, but it did land itself into the New England Journal of Medicine for good reason. Nature has picked up the story and had a good look at it. The science is good.’
 
According to the study, participants who had successfully fought off SARS had very high levels of neutralising antibodies against SARS-CoV-2 even after just one dose of the Pfizer vaccine.
 
Their blood samples showed strong resistance against current variants of concern, including Alpha, Beta and Delta, as well as five bat and pangolin sarbecoviruses – a sub-genus of coronaviruses that includes SARS-CoV-1 and SARS-CoV-2.
 
‘No such potent and wide-ranging antibody response was observed in blood samples taken from fully vaccinated individuals, even those who had also had COVID-19,’ Nature reports.
 
‘The researchers suggest that such broad protection could arise because the vaccine jogs the immune system’s “memory” of regions of the SARS virus that are also present in SARS-CoV-2, and possibly many other sarbecoviruses.’
 
As a result of the findings, the authors believe a future vaccine could be developed that would protect recipients against any evolving variants of SARS-CoV-2, as well as other coronaviruses that might cause a future pandemic.
 
Dr David Martinez, a viral immunologist at the University of North Carolina at Chapel Hill who is also trying to develop a ‘universal coronavirus vaccine’, told Nature that the study is a ‘proof of concept that a pan-coronavirus vaccine in humans is possible’.
 
However, the study authors say further investigation is needed, including on the responses in a wider cohort of SARS survivors, as well as to see if a similar antibody reaction is produced if the process is reversed. This is described in the study as ‘priming from the SARS-CoV-2 clade followed by boosting from the SARS-CoV-1 clade’.
 
‘If successful, this will lay a strong foundation for the development of a third-generation COVID-19 vaccine for controlling current and emerging variants of concern, as well as for preventing future sarbecovirus pandemics,’ the scientists wrote.
 
Despite calls for a pan-coronavirus vaccine, the authors say a ‘more urgent and realistic goal’ would be the development of a more focused ‘pan-sarbecovirus’ vaccine, given the high potential transmissibility of viruses contained in this subgenus. 
 
For Professor Thompson, the implications of the study are a cause for optimism and a sign that vaccination may be even more effective in the future.
 
‘We got spoilt by the smallpox vaccine where you have your one injection and you’re done. In reality most vaccines are not overly effective,’ he said.
 
‘The influenza [vaccine] doesn’t work that way. It only lasts for about six months and it’s not overly effective.
 
‘The current COVID-19 vaccines are so fast-tracked. All the studies are done appropriately and it’s been highly effective. But ordinarily you wouldn’t get the side effects, ordinarily you wouldn’t need two doses, ordinarily you wouldn’t need to do the cold chain storage.
 
‘This is the Holy Grail, isn’t it? If we could actually have a vaccine that covers all the variants, that would be fantastic.’
 
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