The United States they return to counting a thousand deaths a day for Covid. There Great Britain hit 170, a record since March. Israel reviews 8,700 infections, as it had not happened since January, at the dawn of the vaccination campaign. Nine out of ten hospitalizations are for non-immunized people, but against the fast-running Delta variant, many countries now put the third.
It is the third dose of the vaccine, the help that is sought to crush the contagion curve again. The new round of injections in Israel it has already involved 1.1 million citizens out of 9.3. The Usa yesterday they announced the date of the restart: 20 September, starting with the immunocompromised and the elderly to reach all citizens, 8 months after the second dose. From next month too Germany, France e Great Britain they will offer a further reminder to the frail, guests of the RSA and health personnel.
“The third dose is urgent for frail patients.” The appeal of the director of the Regina Elena
by Elena Dusi
The appeal of theWorld Health Organization (“Let’s vaccinate the countries that have not even received the first doses, before thinking about the third ones,” the director had asked Tedros Adhanom Ghebreyesus) seems destined to go unheard (even animals have been vaccinated in some zoos in the United States). “Two problems overlap here,” he admits Guido Forni, immunologist of the Accademia Nazionale dei Lincei. “The ethical one of equity between the countries of the world and that of frail and elderly people, who actually need a further stimulus”. The doubt is that 9 months after the first administration the effectiveness of vaccines begins to weaken. This is insinuated by Israel, where half of the new infections today occur in people vaccinated with two doses.
Observing the infections in June and July, it was realized that those vaccinated in January are 2.3 times as likely to become infected with respect to those in April. Of course, the first vaccinated have a higher average age and it is possible that their antibodies were already originally lower, because the elderly respond less to immune stimuli. The Delta variant has meanwhile installed itself in the world, with its replication index between 6 and 7, at least double that of the Wuhan coronavirus. “It makes sense that the antibody titer starts to drop over time, it happens with all immune responses. With Covid we still don’t know how long the immune memory induced by vaccines persists ”explains Forni. “Perhaps the first data on efficacy, so fantastic, had deceived us a little. They proved to be very useful in reducing severe forms, but in vaccinated people we expected a lower number of infections ».
The American Centers for Disease Control, in recommending the third dose, yesterday cited three studies that indicate declining protection, it is not clear whether due to the weather or the Delta. According to US data, the effectiveness of the two doses of Pfizer or Moderna among healthcare personnel and RSA guests dropped from 74% in the spring to 53% in June and July. Protection from hospitalization and serious illness remains very high. Also in Italy infections among health personnel – almost completely immunized since January – have returned to rise in the last month, exceeding 1,300. Among the vaccinated in the first hour there are also the teachers, who will return to the classroom in less than a month.
Vaccine, here is who answers better: women, young people and thin people have more antibodies
by Elena Dusi
Reinforcement of antibodies is expected from the third dose. “In people over 65 it is certainly advisable, net of the ethical problem” according to the immunologist of the Lincei. “At a certain age, the immune memory vanishes earlier, like that of the brain. After having seen a movie once, he remembers little. The second time is already better, the third is difficult for any detail to escape. That’s why the Food and Drug Administration – the authority that regulates vaccines and drugs in the US – a month ago ruled out the third injection, but today it’s backtracking. Its counterpart EMA (European Medicines Authority) is also considering the further recall, after having ruled out the opportunity at the beginning of the summer. And the first efficacy data arrived yesterday from Israel: after the third injection the protection reaches 86%. Of the 150,000 tri-vaccinated people examined, 37 became infected. In a control group that had had two doses, 1,064 were infected. Both Moderna and Pfizer are also experimenting with an ad hoc vaccine against Delta, which should arrive towards the end of the year.
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