It is questionable how much longer current Covid-19 vaccines will be used as they have largely done their job in preventing mass deaths, and scientists should focus on developing a vaccine that stops transmission of the virus, according to leading scientist Sir John Bell.
The huge success of Covid vaccines in countries able to get them has led to sharp declines in deaths and severe disease from the virus, even though the latest Covid variant, Omicron, has spread rapidly.
“We need a new vaccine to stop transmissions and there are lots of interesting ideas,” said Bell, regius professor of medicine at Oxford University and a former member of the UK vaccine taskforce who has worked on the Oxford/AstraZeneca Covid jab.
“Deaths from the disease, those really awful deaths, had largely been eliminated by the late spring [2021], and they rumbled along, at a very low level and very close to baseline, and they’ve continued to rumble along almost in a flat line since then,” he said.
The baseline represents the number of UK deaths that should be expected based on average mortality data before the pandemic.
However, the spread of coronavirus remains a problem, leading to hospitalisation of vulnerable people, keeping many off work and leaving a number of people with long-term health issues. Scientists are pinning their hopes on nasal sprays, rather than shots in the arm, which aim to produce strong immune protection in the nose and throat, to block Covid infections at the gates. More than a dozen trials are under way.
“It’s an interesting question whether any of the [current] vaccines have a long-term future,” Bell said. “None of them are very good at stopping transmissions,” he said and as variants emerged “they get less good over time” at preventing people becoming sick.
“So you’ve got a couple of choices. You can make a new vaccine every time you see a variant and it may be less good than the original vaccine so you end up chasing your tail. You could probably use the existing vaccines to boost the elderly people at some sensible interval, preventing them from dying. We have to wait and see if we do see more deaths in that population … but we haven’t seen them yet.”
The Canadian immunologist also said “the booster had no impact on deaths, despite all the rah-rah,” suggesting that two vaccine doses were enough to prevent death and serious illness. “The booster was driven by the perceived need to increase neutralising antibody levels,” he said.
“This might have some impact on transmissions and symptoms, although we all know it does not do much for Omicron transmissions, but protection against mortality has other correlates and the death rate in doubly vaccinated people looks very low. Indeed the vast majority of deaths are unvaccinated.”
The UK’s current spring booster campaign, the fourth jab, is targeted at the over-75s, care home residents and those who are immunocompromised.
Bell is in favour of another round of booster shots in the autumn for those over 65 and vulnerable people with poorer immune systems, but like some other experts, said he saw little point in offering repeat vaccinations to healthy younger people, children and teenagers, unless a more serious Covid variant emerged.
He said he was “not massively enthusiastic” about immunising very young children. “Their risk of severe illness is low with Covid and they almost never die. If we had a great transmission blocking vaccine then doing kids would make sense but we don’t. Most of the world is going to get Covid, we need to get used to it.”
He estimated a “very high” chance that any new variant will be relatively mild, like Omicron, while the chances of a more lethal variant emerging were “very low but not nothing”.
“We need to be on the lookout for a highly pathogenic variant that might start killing people at scale and is evading the vaccine response but we see no sign of that today.”