Tuesday, December 7

Spain, at the forefront of the world in second doses, a strategy under debate | Society

Spain is one of the countries in the world with the highest percentage of the population fully immunized thanks to the covid vaccines: 2.45% have already received both doses. It is only behind Israel, a prominent leader with almost a third of the population; The USA (4.83%) and three European countries that are only a few tenths ahead: Denmark, Serbia and Romania, according to data from Our World in Data, from the University of Oxford. What on the one hand is good news – doses are given at a good rate as they arrive – has a b-side: there are indications that a single dose can give ample immunity to those who receive it, so every second that is prick can be interpreted as an injection that is not protecting another person.

The United Kingdom was already working with this hypothesis. That is why Spain is ahead of this country in second doses and far behind in first: a quarter of its population has already received a puncture by 3.5% of the Spanish. What many viewed with skepticism as a new experiment by the Boris Johnson government is being backed up with data. An investigation published this Friday in The Lancet, shows that the Pfizer drug is 85% effective in symptomatic infections after the first dose. The study, carried out among more than 7,000 workers at the Sheba hospital, in the Tel Aviv metropolitan area, confirms the drastic reduction in the rate of infected between 15 and 28 days after receiving the initial inoculation, reports Juan Carlos Sanz. On the total of those infected by the coronavirus, including the asymptomatic, the level of protection of the vaccine is set at 75%. This is in addition to a letter published Wednesday by two Canadian scientists in New England Journal of Medicine in which they defend that the first dose of Pfizer has an efficacy of 92.6%, according to studies by the pharmacist itself and the US Administration.

Canadian scientists admit that there is uncertainty about the duration of protection that is achieved with a single dose, but they argue that revaccination after a single month provides less benefit in the short term. “Given the current vaccine shortage, postponing the second dose is a national security issue that, if ignored, will undoubtedly result in thousands of hospitalizations and deaths this winter in the United States,” they say.

Spain is doing what the regulatory agencies say, administering the second dose when it is due, according to the drug leaflets. Amós García Rojas, president of the Spanish Society of Vaccination, admits that the evidence can change rapidly and that new studies that emerge must be examined to analyze a change in the guidelines. But he defends that today it is done as established by the European Medicines Agency (EMA, for its acronym in English), especially in a context in which the arrival of vials is expected to accelerate and, therefore, the rate of immunization of the population rises.

In the case of Pfizer, the EMA recommends 21 days, although it admits that it can go up to 42 days without compromising its effectiveness. These 21 additional days of margin are not trivial, it may mean puncturing 1.3 million more people with the first dose, at the rate that they are now reaching Spain. Moderna’s recommendation is to space the doses 28 days apart. And 12 weeks for the third currently approved in Europe, AstraZeneca.

Spain has already changed the step in the vaccination strategy more than once, a document that by its own definition, with new drugs and with various indications, has to change. Given the evidence that people already infected generated a strong immune response, it was recommended not to vaccinate them until six months after the diagnosis of the infection.

The vaccine is noticeable

Everything indicates that the effect of vaccines is already making itself felt in Spain. The residences, where more than 90% of the residents are already fully protected, show more and more encouraging data. Outbreaks in these centers have been reduced by 75% in the last month in three weeks, a drop more than double that of outside them. And more and more autonomous communities report decreases in cases and deaths.

One of the clearest has been in Asturias, which was also the community that administered vaccines the fastest among these elderly. The graph that accompanies this text shows it perfectly: deaths in residences and outside of them were practically in parallel. The same thing happened the first weeks after the vaccines were administered, which is not surprising, since it takes between 10 and 12 days to take effect and deaths are the last statistic in which a decrease in incidence has an impact. But three weeks after the administration of the first doses the two lines of the graph took different directions. While deaths outside the residences continued to rise, in them they dropped dramatically.

For this clue to become solid evidence, a study will be required in which the data is analyzed eliminating all possible confounding factors. But Mario Margolles, director of the Asturias Health Observatory has few doubts: “It is evident that they are having an effect, because all other factors are the same and we are seeing a drop in mortality from the first dose. Seeing this gives us great emotion and gives us great relief, ”he explains. The third wave arrived in Asturias somewhat later than the rest of Spain and this allowed, in his opinion, that the vaccine had time to act and prevented hundreds of deaths that would have occurred without it. Margolles also admits that the vaccination process is showing that immunizations are not working 100%. As the studies indicated, there is at least a 5% failure. “We are seeing some cases that become infected more than a week after the second dose, but it falls within what is expected,” he says. In any case, surveillance also shows that the levels of viruses found are generally much lower, leading to less severe (or asymptomatic) disease and lower levels of transmission.


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