What next? The story of Covid vaccines has only just begun

The success of the UK’s vaccine roll-out is cause for cautious optimism. But securing the population its double doses won’t be the end of the road for Covid vaccination. Uncertainties about supply, re-vaccination and adapting existing vaccines lie ahead.

“It’s very unlikely that re-vaccination will be any more frequent than once a year – and perhaps even every two years,” says Professor Robert Dingwall, a medical sociologist from Nottingham Trent University and a researcher in genetics and evolution. For vulnerable groups, it may well mirror the flu vaccine: “Both will be annual visits to the GP – flu jab in the autumn, Covid vaccine in the spring”.

Establishing the length of protection vaccination provides is critical. But another equally important question looms: will the vaccines themselves lose their efficacy in the months and years to come? A growing number of Covid-19 mutations brings with it growing fears that the usefulness of our current vaccines will be compromised.

“We know that changes in the UK variant are not a problem in terms of vaccine efficiency,” says Professor Lawrence Young, a virologist at Warwick Medical School. Indeed, a study conducted this month concluded that the Pfizer and BioNTech’s vaccine is effective against the key mutation in the new variants found in both the UK and South Africa.

Yet the consensus shared by Prof Young and others in his field is that “there will come a time when we need to tweak the vaccine.” Exactly when this will be is hard to say. Prof Dingwall says: “It could happen tomorrow, it could happen in five years’ time. The mutations, the variations, are essentially random, and there’s no way to predict.”

When it comes to attempting to delay mutations, vaccination itself is a double-edged sword. On the one hand, mass-vaccination means there’s less of the virus circulating and less chance for it to mutate. On the other, Prof Young warns, mass-vaccination encourages vaccine-resistant mutations to evolve – a situation similar to what we‘ve witnessed with antibiotics. When it comes to tweaking the vaccine, it’s a matter of when rather than if.

How difficult will it be to change existing vaccines? Not too hard, according to Ugur Sahin, co-founder and CEO of BioNTech. Sahin is confident that the mRNA technology (used in the Pfizer/BioNTech and Moderna jabs) allows vaccines to be altered “extremely fast” when faced with a novel virus variant.

“We can change the sequence of the vaccine within a few days and we could deliver a new vaccine within six weeks in principle,” he says.

Here, the Pfizer and Moderna vaccines have a considerable advantage over AstraZeneca’s, says Dr Zoltán Kis, research associate at the Future Vaccine Manufacturing Hub at Imperial College London. While the active ingredients for the mRNA vaccines can be produced in two days, it takes two months to make the active ingredients for the AstraZeneca vaccine.

As for major testing delays, Prof Dingwall hopes they would all avoid these. For minor tweaks, “the regulators are unlikely to demand evidence at the scale of a clinical trial. They’d almost certainly be satisfied with laboratory results.”

Of course, keeping track of mutations will be critical in the months and years ahead. Last week, a new national research project, the ‘G2P-UK’ was launched to study the effects of emerging mutations. This comes on top of the extensive virus sequencing work already being conducted by Covid-19 Genomics UK (COG-UK). When it comes to monitoring new strains, “surveillance using genomics is so important”, says Prof Young. “And we happen to be quite good at it in the UK”.

The verdict on the UK’s vaccine supply over the coming months and years is equally encouraging. Dr Kis predicts that there will be a growing trend for outsourcing the manufacture of vaccines. Currently, this is limited by the intellectual property rights vaccine developers own. “They want to maintain the quality of production so they are very selective about who they allow to produce their vaccine,” he says.

But he expects that, with time, more and more companies will start to produce it. “It will still be sold as Pfizer or Moderna and so on but it could be manufactured anywhere.” These contract manufacturers will help to keep supply flowing.

There’s little reason to fear shortages, according to Prof Dingwall. “Factories can get built quickly. And suppliers can come on stream”. There is a caveat, however. “You can’t just clear the virus out of your own country and put a firewall round it”, he says. If we’re looking at managing an endemic infection in a globalised world, this approach will always fall short. Prof Dingwall isn’t alone in predicting that the greatest vaccination challenge in the years ahead will be ensuring distribution reaches every corner of globe.

In many ways, attempting to second guess the trajectory of a mutating virus feels like a losing game. What we can be sure of is that coronavirus will not be eradicated any time soon. As for a more optimistic prediction: tweaking existing vaccines is unlikely to be too difficult. Rather, like the flu jab, it may just be a case of yearly fine-tuning.