Anti-Covid vaccines: why the government is choosing to space the two injections by 42 days
DECRYPTION – While the executive previously refused, the Minister of Health Olivier Véran announced that the spacing between the two doses increased from 4 to 6 weeks, or 42 days. Why this about-face?
As the saying goes, “it’s never too late to do well“. Interviewed in the Sunday newspaper , the Minister of Health Olivier Véran announced that the spacing between the two injections of the vaccine against the Covid-19 would henceforth pass from four to six weeks, or 42 days. However, a few months earlier, the government had refused to follow this protocol, when such guidelines had already been proposed by the WHO and the Haute Autorité de Santé.
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At the end of January, immunologist Alain Fischer, chairman of the Vaccine Strategy Steering Committee, and virologist Marie-Paule Kieny, head of the Scientific Committee on the Covid-19 vaccine, presented several arguments against a 42-day gap between the two doses: “lack of efficacy of the first dose, absence of such data in clinical trials, concern about the protection of very old people, risk of forgetting the second appointment … “, remind him JDD. So why has the government changed its mind?
Successful bet for England
At the beginning of January, the World Health Organization and the High Authority of Health had indeed recommended to the French government to widen the spacing between the injection of the two doses of vaccines of 6 weeks. After a debate between favorable and unfavorable authorities, the government had finally chosen the path of prudence, believing that a postponement would not have in fine one “minor impact on the timing of vaccinations “.
The British example has shown the contrary. While the United Kingdom was the most bereaved country in Europe, the English Prime Minister, Boris Johnson, made the choice to widen the spacing between the injections, thus going against the recommendations of the large groups which market vaccines against Covid-19.
Today, with more than 32 million people over 50 having already received a first dose, the UK is high on the global vaccination campaign. On Saturday, April 10, the number of new cases was estimated at 2,589, and that of deaths, at 40 people. On March 28, no deaths linked to Covid-19 were noted in London. A first for almost six months. Unsurprisingly, England should be able to lift their restrictions on June 21.
Another element may explain the government’s flip-flop over the difference between the two doses: studies have recently been published on the subject. Indeed, last January, Olivier Véran had chosen caution: “We are faced with a part of the unknown, I choose the security of validated data“, He declared during a press briefing.
Since then, several studies have been published, including a first review by the British Department of Health (Public Health England) at 1er March, which was very encouraging. It shows that Pfizer and AstraZeneca vaccines are 80% effective in preventing hospitalizations in people over 80 years old, between three and four weeks after the first dose. According to the Pr Hare, “The two vaccines seem to correctly prevent Covid-19 infections until 34e day”.
These data join other scientific work which pleads for a spacing of the injections. On February 22, the findings of a study carried out in Scotland – the first to be carried out at the level of a country – among 5.4 million people were posted online. They show a very high efficacy of the vaccines from the first dose, with a peak between the 28e and the 34e day for the Pfizer and BioNtech Comirnaty.
Try the experiment, but without the elderly
Questioned by the JDD, Doctor Anne-Claude Crémieux wants to be cautious all the same: “Twenty-eight days after the vaccines, whatever they are, the prevention of hospitalizations is about 80%. The English strategy is not to prevent infections, because for that a dose is not enough, but to reduce the number of severe formss, ”she explained to the weekly.
The real limits of the spacing between two injections concern the elderly. “87% of UK failures occurred in patients over 80“, indicates the professor. “In this population, it appears that the immune response obtained after a dose is insufficient to prevent hospitalization.“. It is therefore judicious, for her, to try the experiment, but without the elderly.
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