Pfizer vaccine: Israel begins third dose and opens debate | Defenses decrease over time but specialists doubt the need to revaccinate for the moment

Israel, one of the fastest growing countries in its covid vaccination campaign, started applying third doses of Pfizer to protect over 60s. Although this health strategy remains it has not been recommended by regulatory bodies (like the European Medicines Agency or the United States Food and Drug Administration), the country becomes the first country to choose this path. But there could be more: Germany and United Kingdom have already announced that they will be giving a booster in September, while Uruguay and Chile they are the first to favor this option in the region.

In addition to the elderly, the group who will receive the third puncture is made up of immunocompromised people and individuals due to underlying pathologies. The requirement? Have received the second dose more than five months ago. The objective of the Israeli government is to vaccinate next week one and a half million people who find themselves in this situation, against the spread of Delta and the increase in cases which already stands at 2,000 daily infections. Likewise, this new injection would serve as a reinforcement because, on the basis of studies carried out by the company itself, the tusks fall over time.

“Pfizer has circulated the idea of ​​the need for third doses. He presented a study in which, After a few months, the effectiveness of the vaccine against the infection drops from 94 to 86 percent. Although he goes down, the protection is still very high», He specifies Ernesto Resnik, Argentine molecular biologist and biotechnologist in the United States. Then complete: “Normally, some antibodies drop; it’s natural indeed: if the body does not identify the pathogen again, it assumes that the danger is gone. In the United States, for example, the FDA’s response was that a third dose was not needed.”. And he adds: “You have to understand that Pfizer is a company and seeks to sell vaccines”. In the geopolitical dispute over access to resources, in many cases, the question is most often focused on the role of States, without paying too much attention to the main actors of the pandemic: the laboratories. The economic interest of companies is inescapable; as reported by the Company’s Chief Financial Officer Frank D’Amelio, Pfizer made $ 7.8 billion from its vaccines in the second quarter of 2021, while at the end of the year it expects to get another $ 33.5 billion.

In the same vein as Resnik, Daniela Hozbor –Biochemist and principal investigator of Conicet at the Institute of Biotechnology and Molecular Biology of La Plata– expresses: “There are several countries which are analyzing the application of the third doses. Pfizer had previously avoided this possibility because its scientists observed that the protection diminished somewhat. However, there is no argument that supports this strategy and makes it universal and extrapolated to other nations”. Then he comments: “I think it would be nice to give this discussion to specific populations, like the elderly, whose immune system is senescent and may need a boost to be able to maintain an adequate response ”.

It is necessary?

In Israel, despite having over 60 percent of its population immunized with two doses, have put in place new restrictions, with which the dream of the herd and the return to normalcy were postponed. “There are works that speak of a reduction of 40% and others of 60% for symptomatic disease. However, in everything I have read I have always observed that the tests take few patients, so these are numbers that must be analyzed with a grain of salt. Anyway, protection against serious illness remains very strong“, Thought Juan Manuel Carballeda, Conicet researcher at the Emerging Viruses Laboratory of the Institute of Fundamental and Applied Microbiology of the National University of Quilmes.

If the protection still displayed by two doses of Pfizer “is very strong”, how do you explain the strategy for which Israel opts? Resnik is developing a hypothesis to understand why the country begins with inoculation of a third dose. “Israel has a very rare deal with Pfizer, whereby it got vaccines before everyone else. It makes me doubt that this is not a move to help the company sell even more doses. It seems incredible to me that they are giving an extra dose: it’s true, now there are cases of Delta, but the situation is under control.. They hardly register deaths, seems absurd», He notes. Israel has reported an average of three deaths per day over the past week.

“It could also happen that the Government wants to give a positive signal of care to its population., express a sense of tranquility. But I can’t explain it to myself ”. In this sense, Hozbor emphasizes: “However, the variants do not indicate the need for an additional booster dose. With two doses, the effectiveness of the vaccines drops a little, but it remains high. Pfizer, for example, was offering 94% against the original Wuhan virus and up to 88% with Delta. It is not that it is a disaster, on the contrary, ”explains the specialist.

What could happen in Argentina?

The present confronting the countries which have vaccinated the most and which – slowly – is beginning to make itself felt in Argentina, is characterized by a decoupling between the number of infections and deaths: while infections with the new variants could increase, deaths tend to decrease because the protection against hospitalizations and deaths offered by vaccines is very high. “We have seen it in Israel, but also in many European countries. Decoupling is a prime example of the effectiveness of vaccines. Now all of a sudden it occurs to them that two doses do not work as well and that they would need another booster. Maybe in places like Chile and UruguayWhere there is popular pressure to get vaccinated with Sinovac, it is more understandable to give a third dose of Pfizer. But from my point of view even then, it would not be necessary now. You only have to look at Uruguay’s contagion curve as it fell meteorically to realize it, ”explains Resnik. And he concludes: “It is impossible to ignore the amount of field data we have. The reality is indisputable: vaccines work great”.

“It should also be borne in mind that the first to insist on the need for a third dose are the pharmaceutical companies.. If we were to reflect on the strategy that our country will develop in this regard, it should be discussed in depth. With the SputnikFor example, combining two different adenoviruses is not that easy. If necessary, a third inoculation with another vaccine could be considered, ”warns Hozbor. Studies combination of vaccine formulas carried out by the world and also by Argentina, serve to take a step forward and project possible solutions to the new needs that Sars CoV-2 demands. “The third doses are perfectly possible. The option that attracts me the most – because that’s what gives the best results – is to combine vaccines with different technologies. Precisely because they wake up different parts of the immune system. This was seen in the case of AstraZeneca with Pfizer, ”explains Carballeda. Then he projects: “All the more so with the emergence of new, more transmissible variants that reduce immunity against contagion. In Argentina, this will be an issue that may need to be addressed in the coming months.”.

Beyond advice, there is one damning fact: while Israel is aiming for the third, there are countries in Africa that have not even given the first. The planet’s inequality in access to strategic resources during the pandemic is overwhelming.