Vaccination against Covid, the immunologist Viola: “The time factor is fundamental. The selective pressure could bring out variants”

The vaccination campaign in Italy it proceeds and runs quickly. And the time factor is much more important than it may seem. But there are many issues surrounding mass immunization. We asked some of these questions to the teacher Antonella Viola, immunologist and full professor of Pathology of the Department of Biomedical Sciences of the University of Padua, who is also among the scientists who contributes on social networks to answer one question a day on Sars The 2. Who says about mass immunization: “The time factor is still fundamental” and that I cannot remain parts of the world discovered in some way: “We can all be saved together”.

Current vaccines are 95% effective, how will you understand and identify that 10% range where it was not effective?
95% is very high. No vaccine is 100% effective so nothing strange. If we immunize at least 70% of the population, that 5% will still be protected by the community. If you want, you can do a serology to see how our immune system has responded, but I would absolutely not want to encourage the race to serology.

As long as large sections of the unvaccinated population continue to exist (Africa and beyond), will the risk of the pandemic return to a sort of systemic ping-pong persist? Are we all saved together?
Yes, we are all saved together. Community immunity (only possible with a highly effective vaccine, after having approved the pediatric vaccine or having reduced the 33% of people who declare they do not want to vaccinate) can protect us from variants that are neutralized by the antibodies induced by current vaccines . If the virus mutated in a way that would make the vaccine ineffective, we would be discovered again, wherever in the world the mutation were to occur.

Vaccination is important and we are witnessing the start of a historic mass vaccination. But during a high circulation of the virus can one press – involuntarily – towards a resistant virus mutation / selection?
Yes, it is possible. The selective pressure exerted by the vaccine could lead to the emergence of resistant variants. But this also happens as a result of the normal immune response. However, the time factor is fundamental.

Vaccinated people can contract the virus, but can they also be contagious? Is there a difference between vaccines (Pfizer, Moderna)?
There is no difference between vaccines because they are extremely similar. Preclinical data on macaques suggest vaccinates are not contagious. Furthermore, for Moderna there are data that suggest the same thing in humans. This does not mean that Pfizer does not do it: we just do not have the data available. I would be extremely surprised to find that vaccinated people can infect, it is unlikely for many reasons.

Can pneumonia vaccines also be protective against Covid19? Is there a statistic that relates the group of positive individuals to the subgroup of vaccinated against pneumonia?
Absolutely no. There is no solid data that can suggest that the activation of the non-specific immune response can protect us from Sars Cov 2.

Pfizer cannot be administered under 16 and Moderna under 18. How much will teenagers affect the circulation of the virus considering the best scenario in which all at-risk groups will be vaccinated?
Our priority is to vaccinate those at risk of severe disease, not only to protect people but also to ease the health system. Then you can think about the rest and you will have to do it in order not to give the virus the chance to mutate. But it will have to be done globally because even if we all vaccinate in Italy or Europe and the virus continues to turn and change in Africa we cannot consider ourselves safe.

We read on social #novax that those who get vaccinated could then be positivized – due to the vaccine itself – but is this possible?
Nobody can be positivized as a consequence of vaccination. The vaccine induces the production of the Spike protein which is broken up and presented to the immune system to generate antibodies. Who gets vaccinated does not become positive, does not have the virus, does not infect.

One of the most popular arguments on social media – again by no-vaxes – is that which refers to a percentage of adverse (anaphylactic) reactions 10 times higher than standard vaccines. How worrying is this compared to the risk / benefit ratio?
It is true that these vaccines have a higher risk of anaphylactic reactions: to date, 11.1 cases per million vaccinations. For this reason it was decided to avoid vaccination in the case of patients who are at high risk of severe allergic reactions. But it is necessary to evaluate case by case because close surveillance after the administration of the vaccine could be enough, even in highly allergic people, in order to intervene promptly.

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