Coronavirus vaccines: the world is wondering if …

The Covid-19 vaccines were manufactured in less than a year and this sets a real precedent in the universal history of science. These are technologies with which many countries in the world – including Argentina – have initiated mass vaccination processes in a scenario marked by a noticeable increase in cases. New variants, shoots and second waves paint the portrait of a good part of the nations, be they powerful or poor. The conflict that pharmaceutical companies warn, in a health emergency scenario, is that achieving collective immunity (with 70% of the population vaccinated) will take several months and that compliance with the agreed production volume seems more difficult than expected. he ventured. Thus, the questions that arise are the following: How best to use the doses available today so that they reach more people? Would it be acceptable for countries to change strategy and vaccinate more people with one dose and delay delivery of the second for those who have already administered the first? In the end, how can you save more people?

“These are questions the world is asking and in some places they are already being answered. The pandemic situation in many countries has changed dramatically, in a very negative way, with the number of infected people extremely digestible. In United Kingdom and, within it, in specific cities like London, covid is out of control. So the strategy they decided on is, first of all, try to vaccinate as many people as possible “, describe Daniela hozbor, biochemist and principal investigator of Conicet at the Institute of Biotechnology and Molecular Biology of La Plata. Then he continues his reasoning: “In this way, They are considering extending the time between the first and second dose. However, some pharmaceutical companies refuse to do so because they do not have data on the efficacy in the event of an extension beyond what is stipulated, which generally ranges from 21 to 28 days ”.

Moral dilemmas, but this must be understood in light of the scientific evidence. Each of the nations will have to decide on the public health strategy to be implemented and, above all, analyze, evaluate and reflect on the benefits and problems that each path taken could bring. One of the crux of the question is whether, on the basis of clinical trials carried out by the different laboratories in charge of the different vaccine platforms, the administration of the second dose should be delayed. More taking into account that, in some specific cases, the second doses offer different protective components, like Sputnik V, which works with two specific and complementary adenoviruses. From Pfizer and BioNTech, they reported that they had no proof that their drug was effective when the first and second doses are given 21 days apart; While for that of Moderna, the correct period is 28. They are not responsible if applications are filed after the deadline.

United KingdomFor example, it is the country with the highest death rate in the entire European continent and, hit by a different variant of Sars CoV-2, it is close to 70,000 cases per day. As no one is immune to logistical problems – and although it already applies those of Pfizer, AstraZeneca and already authorized Moderna – His government decided that it would choose to vaccinate as many of the population as possible with the first dose and that the distribution of the second could be extended by about 90 days. With this, they argue, they could offer immunity to more people.

The problem with this modus operandi, however, is obvious. Clinical trials conducted by pharmaceutical companies with thousands of volunteers followed a very strict protocol: doses, depending on the case, had to be administered 21 or 28 days apart. Efficacy (over 90% in most), therefore, has been tested with two doses and with this time in between; but not following the scheme that the British government intends to implement. Health authorities in other countries like Spain and Germany are discussing it these days. “In a context like this, everything is a challenge and everything is open to being rethought. From vaccinology, in exceptional times like this, it is proposed to use a smaller amount of active substance to reach a larger population. During the H1N1 pandemic in 2009, studies were carried out to find out whether half the dose was enough to immunize societies. A tiered strategy was decided on to prioritize the groups, but the doses previously stipulated in the trials were not reduced. The talks are still there because the goal is to save as many people as possible, but the bottom line is that there is scientific evidenceHozbor raises. Otherwise, the debates take place in the air, without solid arguments.

So what if you only apply one dose? Some laboratories have carried out studies in this regard. With the first dose, Pfizer and BioNTech ensure an effectiveness of 52%, the point is that they do not know how long this effect lasts if there is no second booster dose. In contrast, AtraZeneca reported more promising results: a single dose could be 73% effective. Kiril Dmitriev, managing director of the Russian Direct Investment Fund (RDIF), which finances the development of Sputnik V, has announced that he may make a “lite” version available in a certain time to meet demand. that the product has. He would have, as they expected, a lower level of protection. From there, Hozbor, a reference to the Advisory Committee of the Ministry of Health and the Vaccine Safety Commission (both of the province of Buenos Aires) is developing a proposal on the effectiveness of single-dose vaccines or with versions “Light”. “There are some that are more than 60% effective. So, given the incidence of the disease in various regions, this is a fairly acceptable percentage, or at least it can be considered beneficial. AstraZeneca reported that with one dose its effectiveness reached 73% and Gamaleya announced that its Sputnik V reached 85% ”. Then he said: “What I think needs to be done is that, at least in the worst of settings, higher risk groups, like older people with weaker immune systems, can access both doses.

In United States, the country most affected by the covid, also takes this into account. Some local epidemiologists they proposed to dilute the doses, with the aim that those already available can cover a larger number of people. But the Food and Drug Administration (FDA, the regulatory body equivalent to Anmat in the country) came to a crossroads, said it was premature to suggest changes of this nature and he rejected the option because the effects they could cause by endangering public health are unknown. The European Medicines Agency (EMA) has advised against delaying the second dose of Pfizer-BioNTech vaccine for more than 42 days. If there are no previous studies, on-the-fly testing is not a very attractive horizon. Making decisions in a hurry and without academic support of any kind can be much more damaging than you realize. It’s like flying without knowing how well the parachute is working.

The vast majority of governments continue to support the application of precise doses at specific times. At the same time, in addition to the vaccine, the other fundamental tools already well known and which can be used to curb the pandemic with proven effectiveness are the jugular, social distance and hygiene. Must wait.

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