Scientists are developing a range of second-generation Covid vaccines aimed at expanding protection against the disease.
Candidates include one version that could provide immune defence against many different virus variants, while other researchers are investigating vaccines that would generate responses aimed specifically at blocking transmission of the disease.
Other projects include research into the creation of multiple vaccines that could each tackle different virus strains but would be administered as a single jab in a manner similar to annual flu jabs, which currently combine four vaccines against different strains of the influenza virus.
At present, Covid vaccines are designed to stop infected people becoming seriously ill, to prevent hospitalisations and deaths. It is not known yet how effective they are at blocking viruses passing from person to another.
“There is no indication that any of the new virus variants that have appeared recently are causing more severe disease than the original virus,” said Professor Jonathan Ball, a virologist at Nottingham University. “However, there is evidence that some of these new variants may be better at infecting and therefore spreading in populations that have existing partial immunity following natural infection or vaccination.”
One possible solution is a vaccine – now under development by a team of scientists including Ball – that targets not just the spike protein on the surface of the Covid virus but also another part of the virus, called the N protein.
“Hopefully this should result in much wider response from immune systems and so provide a much broader immunity to the virus,” Ball told the Observer. “And given what we know now about the emergence of Covid virus variants, that could help us strengthen protection against the disease,” he added.
The project, which also involves the immunology company Scancell and researchers at Nottingham Trent University, has reached a stage where manufacture of the new vaccine has begun.
Ball said it was hoped clinical trials of the vaccine could be launched very soon.
“The plasmid that forms the basis of the vaccine has already been used in other medical treatments and is tolerated well in patients,” he added. “So we are hopeful that we can press ahead with clinical trials relatively soon.”
A different approach is being taken by scientists at Bristol University who have started developing a vaccine that could induce antibodies in the nose and throat.
“That is the route by which the virus infects a person, so if you could aim specifically to generate antibodies in the mucosal linings of the upper airways you could help block the virus from infecting someone or from being passed on,” said Adam Finn, professor of paediatrics at the Bristol Medical School, University of Bristol.
“In effect, you would be creating the anti-viral equivalent of those United Nations blue helmet soldiers who control war zones and prevent invasions.”
To try to achieve this, Finn and his colleagues are measuring antibody levels in the mucosal secretions of people who have been given different vaccines against the disease.
“By comparing the strength of these immune responses, we may then be able to predict how good they are at preventing transmission,” he added. “And from there, we could identify vaccines that are best able to stop the virus spreading from one person to another – in contrast to current vaccines that are primarily evaluated on how well they prevent Covid symptoms developing.”
This point was backed by Deborah Dunn-Walters, professor of immunology at the University of Surrey: “The vaccines that we have developed over the past year are undoubtedly incredible achievements, but they are not the end of the story.
“We have started with vaccines that maybe give us around two-thirds protection against getting serious disease and maybe 50% protection against passing on the virus. The thing we have to do is to improve on this. There is still a lot of work to be done if we are to beat Covid.”
Analysing the numbers
After a year of some of the most dispiriting news to afflict the nation in modern times, there has been a dramatic change in accounts about how we are faring in the battle against Covid-19. According to a host of different criteria, the prospects of the United Kingdom emerging from lockdown, in the relatively near future, are looking stronger and stronger.
Numbers of hospitalisations, deaths, and new cases have plunged over the past three weeks, while the UK vaccination programme continues to outstrip those of most other industrial nations. Scientists have urged caution about moving too quickly in response to this barrage of good news. Nevertheless, there is now a palpable feeling that a significant change in the nation’s fortunes is occurring.
This point was summed up by epidemiologist Mark Woolhouse of Edinburgh University last week: “The data look far better than anyone could possibly have been thinking about two or three weeks ago. So we must surely be able to take a more optimistic stance on what it is now safe to do.”
For good measure, other research suggests that both the Pfizer and AstraZeneca vaccines – which were designed primarily to prevent serious illness – also reduce transmission of the virus from one person to another – although it is not yet clear by how much. A relatively high level of transmission blocking would have a further significant impact on curtailing the pandemic.
But perhaps the most encouraging of all statistics comes from Israel which has been the planet’s most energetic nation in vaccinating its population. Targeting its most elderly citizens as priorities, it has – as a result – seen hospitalisation rates for the over-60s plummet compared with those for lower age groups. It is a dramatic illustration of the vaccine’s effectiveness and has clear implications for the UK where early signs also suggest Covid jabs – in addition to lockdown measures – are beginning to cut into death rates.
“The performance of the vaccine is really good news,” said Woolhouse. “You never quite know how clinical trials will translate in a true mass vaccination programme. But the numbers are looking very good. The vaccines protect very well against severe disease.”