Vaccines, “fourth conceivable dose for the elderly and frail categories”
“It must be evaluated in the near future, also and above all on the basis of the trend of the epidemic”. With these words the virologist Fabrizio Pregliasco, member of the Cts of Lombardy and medical director of the Galeazzi hospital in Milan, answers the question of Affaritaliani.it if there will also be a fourth dose of the anti-Covid vaccine. “The virus moves with waves that follow one another like those of a stone in a pond, there are important waves and others that are reduced. The original wave would be less important if there were variants. Given this premise, it is possible that the ‘any fourth dose is no longer universal but targeted, like the anti-influenza vaccination, for the most fragile, elderly and exposed people “.
“It could only be free for those at risk. As to the timing it is impossible to say today because we do not know the effect of the third dose, although its effectiveness should ensure long-term protection. The first two doses gave an imprinting, the third, which is called a booster, serves to strengthen protection over time “.
As for the new Omicron variant, Pregliasco states: “We still need a week to complete the analyzes and studies, but from the information we have today it seems more contagious but with a less important clinical case history. This means that the virus is adapting. better to the guest with fewer effects in terms of possible serious consequences and mortality. There is no confirmation that the Omicron variant avoids vaccines and with three doses the efficacy should be guaranteed.
“Up to now, computer analyzes have been carried out with evaluations performed by comparing the sequences. It emerges that the Omicron variant only modifies the S1 of the spike (a kind of hook of the virus), so it changes the contagiousness capacity. But the S2, which concerns the pathogenicity and therefore the danger, is not changed and this makes us think. In a still not validated study, researchers have shown insertions of rhinovirus pieces caused by a coinfection in a subject. These modifications inserted in the genome could lead to an improvement and a pathogenic reduction of the Covid virus “, he concludes.
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