As new booster rolled out - where next for Covid vaccines?

By the time this year’s winter rollout is complete, all over-50s, elderly care home residents and staff, pregnant women, carers aged 16 to 49, and anyone aged five to 49 in a specific clinical risk group or who lives with someone who is immuno-suppressed, will have been offered the boosters.

For now, healthy under-50s are exempt; the focus is on strengthening immunity against severe disease, rather than trying to slow transmission in younger people.

The programme is starting earlier this year amid concerns about a possible surge in flu from late September, and around half of the 26 million people eligible for the Covid boosters will be given Moderna’s newly-approved bivalent vaccine - “Spikevax” - specially tailored to target both Omicron and the original form of Covid.

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On Tuesday, UK regulators became the first in the world give the go ahead to the dual-Covid vaccine based on the results of clinical trials involving people previously given three standard Moderna doses.

Those given a fourth dose using Spikevax generated around 74 per cent more antibodies capable of latching onto and disabling the Omicron BA.1 variant compared to those given the original Moderna vaccine, developed against the ancestral Covid strain which first originated in China.

Evaluated against the currently circulating BA.4/5 subvariants, there was also evidence of a five-fold increase in antibody levels 28 days after vaccination with Spikevax - although the response was less than half as strong as it had been against BA.1.

June Raine, of the Medicines and Healthcare products Regulatory Agency (MHRA)

June Raine, chief executive of the MHRA - the regulatory body which approved its use in the UK - described the bivalent vaccine as a “sharpened tool in our armoury”.

As the virus has evolved and more and more mutations have appeared on the spike protein (the bit onto which antibodies bind to prevent the virus from entering cells), existing vaccines have become increasingly ineffective at preventing infection - though much less so for severe disease and death.

Nonetheless, adapting the vaccines to a changing virus has been seen as crucial to pushing back against Covid.

Increasingly, the sheer number of people becoming infected has been a much bigger headache for the NHS (due to staff absences or requirements to keep Covid and non-Covid patients apart) than people becoming sick with the disease.

READ MORE: Why Covid reinfections could be a much bigger problem than expected

Exactly how much of an impact Spikevax will have on actually reducing cases remains to be seen, however.

Danny Altmann, a professor of immunology at Imperial College London, said BA.5 - currently accounting for an estimated 80% of Covid infections in Scotland - is so highly immune-evasive compared even to its Omicron BA.1 parent that the new vaccine may offer only “a rather marginal advantage”.

Professor Beate Kampmann, director of the vaccine centre at the London School of Hygiene and Tropical Medicine, said Spikevax will probably achieve only “very partial protection” against BA.4/5 infections, while Jonathan Ball, a professor of molecular virology at Nottingham University, said there was also the risk that Omicron-targeted immunity might have the effect of pushing the virus down other evolutionary paths.

In this scenario, he said, the scientists developing the vaccines to try to counter it become “like the Red Queen in Alice and the Looking Glass - having to keep running just to stay in the same place”.

The vaccine has become increasingly less effective at preventing infections as the virus has evolved, and restrictions eased (top). However, an increasing share of the population being double, triple, or quadruple jabbed has reduced pressure on intensive care from Covid

A worst-case scenario still remains some new variant which evades prior immunity - including vaccine protection against severe disease - and combines the infectiousness of Omicron with the severity of Delta.

There is nothing circulating at the moment that is ringing any of those alarm bells - though surveillance and testing have been stripped back globally.

If there is a vaccine Holy Grail in the battle against Covid, however, it probably isn’t variant-specific formulations, which inevitably see their potency wane and the virus adapts.

Only a vaccine that provided sterilising immunity - preventing infections in the first place, and thus transmission - really would stop Covid in its tracks.

There are scientists working on it, and more than 10 candidate vaccines are already in various stages of clinical trial, including four in the final stages of human testing.

The key difference is that these vaccines would be sprayed directly into the nasal cavity to trigger a mucosal response, rather than being injected into the arm.

The goal is to create a first line of defence against infection in the upper respiratory tract - preventing the virus replicating there, or from ever reaching the lungs.

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Indian pharmaceutical firm, Bharat Biotech, submitted the data from the Phase Three clinical trials of its nasal Covid vaccine to the country’s regulators in July.

The trials, involving around 4000 participants, compared outcomes using the vaccine as both a primary dose, and as a booster.

Dr Krishna Ella, the company’s chairman and managing director, said the vaccine - developed in collaboration with the Washington University School of Medicine in St Louis - was a “game-changer" capable of preventing infection and transmission. 

Dr Krishna Ella, Bharat Biotech

As well as making life easier for the NHS, a vaccine which severely curbed transmission would also make society safer for everyone - not just the 'healthy' majority.

In recent months, thousands of people with disabilities or disorders which increase their risk from Covid - but who do not qualify for antivirals or Spring boosters - have effectively returned to shielding because virus rates have never been higher.

As another booster rollout gets underway, it's worth remembering that "living with Covid" is still a lot easier for some than others.