COVID vaccine weekly: developing boosters for new mutations

COVID vaccine weekly: developing boosters for new mutations


There’s now another dimension to the race to get people vaccinated. The coronavirus is mutating, potentially making current vaccines less effective against it. This isn’t a catastrophe – the vaccines still work. But preliminary data suggests their ability to protect against certain variants of the virus is now weaker.

Anything that undermines control efforts needs responding to, and vaccine manufacturers have duly stepped up. Professor Andrew Pollard, a senior researcher involved in the development of the Oxford/AstraZeneca vaccine, has said a booster that can handle the new variants should be ready by the autumn. Pfizer and Moderna have also said they are looking to develop such boosters. GSK and CureVac are also working on a new vaccine that can handle the many variants now emerging.

Various new variants of the virus have emerged, but the ones causing most concern are those carrying a mutation called E484K. As Clare Crossan, Research Fellow at Glasgow Caledonian University, explains, this mutation has arisen independently in viral variants in both Brazil and South Africa, and is now being seen in the variant thought to originate in the UK.

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Several studies have shown that having the E484K mutation stops certain antibodies binding to the virus. Further studies, in turn, appear to show a slight decrease in the effectiveness of current vaccines against variants carrying the mutation. Much of this work is still to be scrutinised by other scientists via peer review, and the protection offered by vaccines was still deemed acceptable. Nevertheless, if this the virus is evolving, it pays to be well-prepared.

Meanwhile, UK ministers say that the country remains on track to have its 15 million prioritised citizens vaccinated with a first dose by mid-February, with 10.5 million now having received a first dose. Pleasingly, new analysis from the Oxford Vaccine Group also suggests that lengthening the time between giving the first and second doses – which has made hitting this target achievable – makes perfect sense with the Oxford/AstraZeneca vaccine.

A new paper assessing additional data from he vaccine’s phase 3 trial suggests that there is no drop off in protection during the 12-week period between doses, and that in fact, leaving a longer gap between the two appears to make the second dose more effective. The findings of the paper we need to be especially careful interpreting, says Paul Hunter, Professor of Medicine at the University of East Anglia, are those that concern transmission. It’s still too soon to determine what effect the vaccine has on spreading the virus.

Two women in masks greeting one another by bumping elbows
It’s still too soon to tell what effect any of the vaccines have on transmission of the virus.

Johnson & Johnson and Novavax have also taken a first look at how their vaccines are faring in phase 3 trials, and the results look promising, says Sarah Pitt of the University of Brighton. They appear slightly less effective than some of the already-approved vaccines, but they came up against some of these troubling new variants during testing. Assuming the trials continue to go well, these vaccines could be authorised for use later this year.

Britain doesn’t have enough doses yet to vaccinate everyone, but at some point will cross over into have far more than it needs. The UK’s orders for these two new vaccines alone would cover the its entire adult population. Countries that have overordered vaccine doses should therefore think about how they could be redistributed, says Alberto Giubilini, Senior Research Fellow at the University of Oxford. But, he says, sharing vaccines should only start once the vulnerable have been vaccinated.

Sharing, though, isn’t something that comes naturally during a pandemic. The history of bird flu and swine flu could have warned us of that, writes Roderick Bailey, Research Fellow in the History of Medicine at the University of Oxford. Countries have a track record of hoarding vaccines and data – even though this ultimately benefits no one.

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