Despite the fact that the pandemic is evolving positively and the vaccination campaign presages that the dark times we have experienced will not return, we are still immersed in a barrage of apocalyptic prophecies on account of the variants and their supposed devastating effects.

I am not sure if putting some light from a scientific prism on this issue is a losing battle. However, it is important to put the possible impact of variants and highlight that, beyond the scope they may have, the damage that is being done to the health sector may be irreparable.

That viruses mutate and generate variants it is a known fact. Fortunately, coronaviruses have a very limited mutational capacity, but despite this, the variants continue to be stubbornly dramatized. These analyzes commit three very rude mistakes or oversights:

  1. Skip the polyclonal character of the immune response.
  2. Consider the antibodies as central axis of the immune response.
  3. Forget that the variants have to be viable.

The immune system does not recognize a virus, in this case SARS-CoV-2. It independently recognizes many small fragments of it (epitopes). This implies that a virus does not generate an immune response, but rather generates many parallel responses that attack the virus on different fronts.

Therefore, and although change some epitope, this it only affects some of those answers parallel: the rest remain active. In other words, although the virus protects some flank (mutation), there are still many open against which the immune system will continue to focus its attack.

The immune response is dynamic and adapts to virus changes. Antibodies are just projectiles used by the immune system, but they are directed by CD4 + T lymphocytes (also called cooperators or collaborators, for the task they perform). This means that if there are changes in the virus, the immune response can be redirected.

CD4 + T cells recognize epitopes on the virus and store them in memory. Only 23 CD4 + T epitopes have been identified in protein S. That is, for the virus to stop being recognized by these lymphocytes, it would have to change those 23 epitopes (about 300 amino acids of the about 1,300 that make up the S protein).

The B cells, antibody producers, they track the surface of the virus looking for the point against which it can produce antibodies, but they do not have the capacity to produce them on their own. They only do it if the CD4 + T activated by any of these 23 epitopes (superficial or internal) authorize them to do so.

In other words, the B’s are the gunners, but do not have the ability to recognize the enemy, so they only do it if Authorize T CD4 +. These are the officers (there would be 23 different lines) with ability to recognize the invader. The attacker can change some things about his appearance, but either he changes them all or he will continue to be recognized and attacked, because the CD4 + T will recognize some of the 23 points that remain intact and will recruit the B, capable of producing antibodies against the epitope or flank changed.

This can make the somewhat slower response, but much faster what if we didn’t know the enemy. For this reason, there is talk of a relative loss of efficiency of vaccines, but never of making them ineffective.

Variants must be viable

The grossest mistake is to ignore the extent that these changes can have on the viability of the virus. The infection of our cells by SARS-CoV-2 is based on the Complementarity of protein S with ACE2. Protein S acts as a key that unlocks the cell through its lock (ACE2).

When we make a copy of a key and it does not fit well, we file the teeth and we improve its complementarity with the lock. But these changes have to be limited, because if we make too many the key loses complementarity and is useless. The same goes for the virus. They can changes occur in S, but to escape the immune response you would need so many changes that it would lose the complementarity with ACE2 and, therefore, its viability.

The theme of variants and evolution of SARS-CoV-2 it is being approached too lightly, which may cause irreparable harm to the health sector. The persistent apocalyptic proclamation on each variant means that, for a large part of the population, these announcements are already a reason for jokes and lacking in credibility.

This situation reminds us of the fable of Aesop’s lying shepherd*, which tells the story of a shepherd who, to make fun of the rest, continuously warned of the imminent arrival of a wolf without this being true. The result was that, when the predator really arrived, nobody believed him and the flocks were lost.

Exactly the same is happening with the variants. The persistent proclamation about the devastation that each variant is going to produce without, predictably, being translated into real events, determines that credibility is no longer given to these proclamations.

In terms of audience, this strategy has been a success, but the loss of credibility can be irremediable. The healthcare group cannot be represented by showmen and upstart fans of this type of statement without anyone putting a stop to it. In the case of Covid-19, it will not be a real problem, but this image will remain on the retina of the population. To make against other health hazards also have to deal with the people’s disbelief.

Rafael Toledo Navarro, Professor of Parasitology at the University of Valencia.

This article was originally published on The Conversation. read the original.


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