ROMA. It is too early to decide on the third dose for the entire population, but it is instead possible to say that a new recall could be useful to the most fragile: this is the position of immunologist Anthony Fauci according to which the decision is now imminent.
“At the moment we don’t see a need to offer any recalls,” director of the American Institute for Infectious Disease Research (Niaid) and Biden administration expert on the pandemic told media today. And while in the United States the drug control body prepares to give the green light to the third dose of the Covid-19 vaccine for frail people, Fauci judged “likely that a vaccine booster will be given at some point in time. future”.
Also in light of the fact that we are already seeing “in some cases indications of a decrease in protection over time”, he added.
They have already firmly said yes to the third Israel and the United Kingdom; meanwhile, in France, the health ministry reported that five million elderly people are considered to be at “very high risk” health and to which priority is given for the third dose. If even in Italy there are openings towards the possibility of a third dose of more fragile patients, the research world prefers to wait for the data before making any decision. We need data: without this fundamental information on the behavior of the vaccine it is not possible to take a position on the third dose of the Covid-19 vaccine and that is why in the United States data on the effectiveness of the vaccine are constantly monitored.
“The underlying problem is that we don’t understand vaccine protection correlates, we don’t understand why people with very high antibody levels get sick.”microbiologist Andrea Crisanti, from the University of Padua, told Ansa.
“From a common sense point of view, the third dose would be good for frail patients, but when public health decisions have to be made, these must be dictated by experience, common sense and data, and at the moment – he noted – data is lacking “.
The first useful information will come from Israel, which after publishing the data on the efficacy found in vaccinated in batches since last January, is now preparing to administer the third dose.
Israeli Prime Minister Naftali Bennett has decided to accelerate by the administration of the third dose of Pfizer vaccines also to over 50s who received the first two doses over five months ago.
The big problem, for Crisanti, is the eventual arrival of a vaccine-resistant variant: if that happens, he said, the third dose will be irrelevant.
The virologist Francesco Broccolo, from the University of Milan Bicocca also points out the lack of data: “At the moment there are no published data on the third dose, not even a scientific work that can be consulted, e consequently it is not possible to say that the recall can increase the titre of neutralizing antibodies and it is not taken for granted that what may happen “.
The speech relating to the second recall is naturally different, added the virologist, but “in the history of vaccinations there have never been booster vaccines that have come close over time in order to increase the titre of antibodies”.
Neither does the flu vaccine, which instead serves to generate antibodies to a new strain of influenza virus.
As for the SarsCoV2 infection “it is therefore not certain that the booster stimulates a significant production of antibodies”, said Broccoli.
“The booster could probably only be approved for immunosuppressed people,” such as those with HIV infection or autoimmune diseases or who have undergone transplants in which a significant increase in the immunogenicity of the vaccine with the third dose has just been demonstrated, because “they generally respond less to the vaccine“.
Research published in the New England Journal of Medicine and conducted in Canada by the University Health Network also reveals that the third dose is effective in protecting those who have had a transplant.