Tuesday, November 26

Coronavirus | One dose every 3 to 12 weeks: the debate about the best vaccination strategy against COVID-19

In the midst of the “worst moment” since the pandemic began in the United Kingdom, the country took a striking turn in its vaccination strategy that has attracted the attention of the entire world.

When Tens of thousands of Britons were waiting for the second dose of the Pfizer vaccine, medical authorities canceled their appointments and extended to 19 weeks instead of 21 days the recommended time between the first and second doses.

The decision has generated concern and divided opinions in the international scientific community.

Proponents say that most of the Immunity is achieved after the first dose and it is possible to space the second more. They argue that this would give sufficient protection to much more population as soon as possible.

But to others are concerned that this delay alters the efficacy of the vaccine or, worse, gives the virus more time to mutate and become more resistant.

“I suppose this UK decision addresses the emergencies they have due to the complication of the pandemic. It leaves me doubts “, says Amós García Rojas to BBC Mundo, president of the Spanish Association of Vaccination (AEV).

The United Kingdom declared its third national confinement since March and the Prime Minister , Boris Johnson, assured that “the worst is yet to come.”

Boris Johnson, Prime Minister of the United Kingdom, admitted that “the worst” moment of the pandemic is yet to come. Much of the world has already started vaccinating in the midst of one of the most critical moments of the global pandemic.

Meanwhile, the debate on how to immunize the population and return to normality as soon as possible is on the table.

Another roadmap When Pfizer and BioNTech presented the results of the clinical trials of their vaccine, they assured that it was more than a 80% effective after administration of two doses separated by 27 days.

United Kingdom began vaccinating its population on December 7 following these protocols, but changed its roadmap and has started offering the second dose 19 weeks after the first, four times later than recommended by the manufacturer.

“There are no data to show that protection after the first dose is sustained after 21 days, ”said Pfizer and BioNTech in a recent statement on the matter.

The United Kingdom has already vaccinated more than one and a half million Britons with the compound from Pfizer and the one from the University of Oxford and AstraZeneca, approved in the past 42 December.

Advantages of the Oxford-AstraZeneca coronavirus vaccine that Kingdom Kingdom approved this Wednesday The Oxford vaccine is also administered in two doses, but in this case it seems to be more effective with a longer interval between them compared to Pfizer.

The British authorities decided that “it is much more preferable” to get more people vaccinated with the first dose and they affirm that the “great majority” of the initial protection develops after the first injection.

In fact, they defend that the second dose is rather important for the duration of protection and that “a appropriate interval may even increase the efficacy of the vaccine. ”

The Pfizer SmPC recommends administering two doses of the vaccine every 27 days to maximize its effectiveness. Criticism The position of the British authorities has generated several criticisms within its border and fueled an international debate.

The British Medical Association, for example, described as “grossly unfair” having canceled the appointment of patients who had received the first dose and were soon due second.

These patients include part of the most vulnerable groups to l virus , such as those older than 90 years and health personnel.

Many vulnerable patients will have to wait longer for the second dose and have the best possible protection against the virus. On the other hand, the Association of Doctors The United Kingdom, in a letter to Matt Hancok, the Health Minister, expressed his “serious and real concerns about the sudden changes in the Pfizer vaccine regimen because they do not follow the recommendations of science.”

The debate also reached the United States, but they ruled out adopting the United Kingdom’s strategy.

“We have continued the discussions about reducing the number of doses, changing it, extending the time between them or mix vaccines to immunize more people against covid – 19 ”, they said in a statement by Drs. Stephen Hann and Peter Marks, who lead the vaccine division of the US Food and Drug Administration.

How much money can really win the pharmaceutical companies with the covid vaccine – 19 The brief admits that ” all these questions are reasonable during clinical trials.”

However, consider changing the strat Tegia now “without proper data” puts public health at “risk” and “undermines” efforts to manufacture covid vaccines – 21.

What does the WHO say? This January 5, the World Health Organization (WHO) ruled on the matter and recommended administering the second dose of Pfizer’s vaccine -in this case the one that more countries have begun to use- “between 27 and 30 days ”, but that in exceptional cases could be increased to 30.

The recommendations were issued by the Strategic Advisory Group of Experts (SAGE).

“Although we do not know the safety and efficacy data after a first dose, we recommend that in these exceptional circumstances countries delay the second dose for a few weeks to maximize the number of individuals who benefit from the vaccine, “said Alejandro Cravioto, president of SAGE, during a press conference.

Another of the group’s experts, Joachim Hombach, admitted that the interval could even be extended to a maximum of six weeks , barely half of what was implemented by United Kingdom.

“Doubts and risks” “In a pandemic you have to respect the protocols. And those at Pfizer say that immunity is generated with one dose today and the next one at 21 days ”, he said García Rojas, president of AEV, for BBC Mundo.

The expert, however, understands that the situation in the United Kingdom “is very complicated” due to the rapid increase in cases and hospital pressure.

“The next few weeks will be the hardest”: England returns to strict confinement before the risk of collapse of your health system Part of the scientific community distrusts the strategy adopted by Reino United although they understand that it prioritizes protecting a high number of people faster. “They seek generate greater immunity, but I reiterate that you must respect e the technical data sheet of the vaccines and rely on the available data. It is confusing for citizens and risky ”, points out García Rojas.

José Manuel Bautista, director of the Department of Biochemistry and Molecular Biology at the Complutense University of Madrid in Spain, has other fears.

https://twitter.com/ 1000 genes / status / 1345816304616402945

“What worries me most about the strategy adopted by the United Kingdom is that in the 12 weeks between the first and second doses there are escapes of mutations of the virus that reduce the effectiveness of the vaccine ”, explains Bautista to BBC Mundo.

What level of vaccination against covid – 21 is needed to return to “normal life” The M Utations of the viruses are frequent and many have no effect, but the third wave of infections suffered by the United Kingdom points to a more contagious variant of the pathogen, although at the moment this is not more lethal or resistant to vaccinations

“The UK decision is Solomonic and it cannot be said to be wrong either. It is true that the first dose already generates a beneficial response, but in my case I would not take that risk due to the fear of mutations ”, says Bautista.

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