‘The devil is in the detail’: Expert warns vaccine tweaks to protect against variants is ‘complex’
Adjusting the coronavirus vaccines to meet new strains emerging around the world may not be as straightforward as the government hopes, a leading scientist has suggested.
In an in-depth thread on Twitter on Tuesday night, vaccine expert Professor Florian Krammer said there was no need for panic but warned “the devil is in the details”.
He said that early variants of SARs-Cov-2 would not disappear as the new ones emerged, making the manufacture and testing of new vaccines more complex than some had anticipated.
He also warned that while the new mRNA vaccines made by the likes of Pfizer and Moderna may hold up well against new variants of the virus, traditional vaccines may not as they tend to produce a weaker immune response.
Watch: What is the new Covid variant?
“I think the mRNA vaccines and other vaccines that give high titers (Novavax etc.) will still work nicely [against existing variants]. But this is a wake-up call! And I do worry about global vaccine supply since many vaccines for the global market induce lower neutralization titers,” he wrote.
Dealing with the issue of multiple variants emerging at the the same time he added: “We need to prepare for making amendments to the vaccines if needed. Now, you hear from many that this is easy and can be done within weeks. It is not that easy. The devil is in the details.
“Yes, you can just change the vaccine, but it is not the case that a new variant just takes over within a day and the old/wild type variants are gone. So, first you have to make sure that the new variant in the new vaccine also protects against the old variants.
“This experiment has not been done and it is likely that there will be a mismatch in the other direction as well. If that is the case you need a bivalent vaccine. Or two different ones. The bivalent vaccine likely needs extended clinical trials again and that takes time.”
It is possible to protect against several strains of a virus with one vaccine. The current annual flu jab covers off four flu viruses and is updated reasonably efficiently once a year.
The World Health Organization is considering drafting in its “sentinel” labs around the world, which research and suggest changes to the flu vaccine, to do a similar job for Covid-19.
Medicines regulators have also said they are looking at how to approve adjusted Covid vaccines quickly and safely.
Professor Jonathan Ball, a molecular virologist at the University of Nottingham, said it was “early days” for adjusting vaccines. There was not yet enough “real-world” data to judge what the new variants might mean for their effectiveness, he said.
A number of lab studies have indicated that the vaccines do seem to protect against the new UK variant, and this week Moderna said its vaccine neutralised the South African varant, too, in lab tests, albeit less efficiently.
“Provided a vaccine still prevents symptoms, and particularly prevents severe symptoms – and we don’t really know about that – to suddenly say we need to make a new vaccine might be seen to be premature,” Professor Ball said.
RNA vaccines produce very high levels, or titers, of neutralising antibodies. As such, even if their activity was reduced by 10-fold against the new virus, “it is still decent neutralising activity that will very likely protect”, said Prof Krammer.
In plain language: there is some wiggle room with the mRNA vaccines. However, some of the other vaccines, which produce lower levels of antibodies, were more “worrisome”, he added.
“I do worry about global vaccine supply since many vaccines for the global market induce lower neutralization titers,” he wrote.
Whatever lies ahead, the answer is the same as it has ever been. Rather than worrying about tweaked vaccines, people can instead do their bit by trying not to get infected and trying not to pass on the virus.
Less infections mean less mutations, and less mutations mean that these questions about tweaking vaccines can remain theory, rather than life-saving necessity.
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