what would happen if they stopped being effective against new strains

Just before Christmas, the Prime Minister of the United Kingdom announced that they had identified a new “variant” of the SARS-CoV-2 coronavirus much more contagious than expected. Almost at the same time another variant, this time South African, captured the media attention of half the planet. And this very week, Japan has found a new variant from Brazil and the worst thing is that this does not end here.

The experts are convinced that the new variants will not stop appearing and that we must be prepared for it. For this reason, although initial analyzes indicate that vaccines are still effective, this “strain boom” raises a fundamental question: What if any of them manages to outwit the vaccine? Would we have to start over and wait a year for the new versions or could changes be made on the fly?

Can the virus outwit vaccines?

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It is a concern that goes beyond public opinion. “The million dollar question is how important this will be to the effectiveness of the vaccines currently being administered“, He said Jeremy Luban, virologist at the University of Massachusetts School of Medicine, in nature last week.

In general, the first emergency tests sent a message of reassurance: some mutations found seemed to “reduce the immune recognition of the virus by our immune system, but “not to the extent that they can, by themselves, render current vaccines ineffective”, we said December 15. However, we needed studies to ensure it for sure.

The first analyzes confirm this and, from what we know so far, the mutations we are checking do not affect the activity of antibodies produced by the Pfizer vaccine. During these weeks, we will have much more information about what the English and South African variants really are like. But, above all, we will better understand the underlying biology of mutations because, beyond analytically determining the characteristics of current variants, we need to better understand their operation to anticipate future strains.

When the vaccine loses effectiveness

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And, although these varieties do not affect the vaccine, that does not mean that it will always be like that. With so many copies of the virus moving around the world, mutations will continue to accumulate in the coming months and, although as pointed Zania Stamataki, an immunologist at the University of Birmingham, the mutation rate of the virus hinders the rapid emergence of new strains (with substantial differences in their behavior), it is a matter of time before this happens.

In other words, the possibility that vaccines will cease to be effective against a virus like this is on the table. That’s why, as early as December, Pfizer’s technology partner, BioNTech, ad that developing a new vaccine would take them “technically” six weeks. Something that is fully in tune with what we know about the speed of messenger RNA technologies. However, as BioNTech also pointed out, mandatory drug testing could delay the process.

The problem will be in defining which processes and mandatory tests the health agencies will request. On the one hand, it will be a new vaccine. On the other hand, the bulk of safety tests will have already been carried out and going the same way again may not make sense. Fortunately, although mRNA technology is very new, it is not the first time we have faced this problem and there are already defined regulatory channels that, while waiting for the authorities to articulate new ones, can start up and speed up the solution to this problem.

What the flu can teach us about the coronavirus

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If there is a really unpredictable virus, it is the flu. That has forced us to have very fast vaccine development, manufacturing and licensing processes; a few months if we want to be prepared for a “potentially pandemic” strain. To give us an idea, since the presence of a new viral subtype is identified until a stable hybrid form of it is achieved with which to manufacture vaccines, it takes about three weeks. In that time, the most interesting genetic variant must be found, its safety verified and certified that it can grow in embryonated eggs. Then it remains to produce the vaccines, distribute them and, of course, approve them.

Therefore, in Europe, as Otero and Moraga explain of the Hospital Universitari Vall d’Hebron, there are two basic ways to approve a vaccine of this type. The first is the emergency procedure, which is, essentially, what we have seen so far with coronavirus vaccines. It requires “the presentation of a new and complete dossier with all the characteristics of the vaccine.” And a lot of information is requested about the “immunogenicity and safety of the new vaccine.” However, it is common that if the manufacturers demonstrate that the vaccine has been prepared correctly, at the time of authorization they only need preliminary data from clinical trials. In other words, the process would be speeded up by a few months (at the cost of “close monitoring in the post-marketing phase to corroborate vaccine efficacy and safety”).

The other, faster procedure is the “template vaccines” (mock-up vaccines) that began to be used in 2004. In this case, vaccines with “prototype strains” are developed in such a way that, when a new pandemic subtype appears, the process can be accelerated a rapid production of vaccines against the appropriate strain. If the vaccine is produced in exactly the same way, the response in the population is expected to be the same and we have data that allow us to predict its safety profile, this route can be used.

In fact, although the regulation requires that “the approval mechanism based on template vaccines requires having the core document approved (core pandemic dossier) of the prototype vaccine “; as Otero and Moraga remind us, there are ways to proceed without such a document in the event of a pandemic. In the case of H1N1 flu, following the template vaccination procedure, the subtype was identified on April 21, 2009 and the EMA approved the first vaccine on September 24.

That is to say, there are intermediate channels to streamline the authorization process that reduce waiting times and guarantee the safety and efficacy of vaccines. To this day, we cannot know which ways the laboratories will use to obtain authorization from the authorities; However, in view of how everything has accelerated, it is reasonable to think that the times would be even less than those of the H1N1. Either way, we would not start from scratch.

Image | Hospital Clinic


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