Third dose of Moderna and Pfizer vaccines for transplant and immunosuppressed patients: the decision of the American Federal Drug Administration anticipated by the New York Times (and on Friday the FDA’s opinion will be discussed in a panel of the Center for Disease Control and Prevention, or the definitive scientific authority, in the US, on pandemics). The decision will not see a unanimous consensus among the scientists: among them there are those who argue that it is wrong to prescribe a third dose uniformly for such a varied population, for pathologies and response to drugs, such as that of the immunocompromised: some of them in fact, they are already sufficiently protected with the double vaccination, while others, although not very protected by the first two doses, may not even benefit from the third.
Vaccines: third dose for frail patients? Here is what data we have
by Tiziana Moriconi
A complexity that cannot be reduced to a one-size-fits-all approach. A Johns Hopkins University study of 30 transplant patients, who had double vaccinations and had low amounts of antibodies to Sars-CoV-2 because they were poorly reactive to the vaccine, showed that only 14% of them had an increase of antibodies after the third dose. More encouraging results are those of another study just published in the New England Journal of Medicine, which evaluated the response of transplant recipients to the third dose of the Moderna vaccine, with a double-blind experiment (ie the type of experiments that allow to reach the most solid scientific evidence). 120 transplant recipients who had received double doses of Moderna were given a third dose or, as a placebo, a saline solution.
Covid vaccine, Israel: yes to the third dose for over 60s. And the EU is also preparing
Result: The group that received the third dose of the vaccine had substantially higher immunogenicity values. Immediately after inoculation, patients who received the third dose had a mean virus neutralization rate of 71%, compared with 13% in the placebo group. And after 4 months of inoculation, 55% of patients who received the third dose of the vaccine had a quantity of neutralizing antibodies greater than 100 units per milliliter, compared to 18% of patients inoculated with placebo.
Covid vaccine, fragile alarm is: “Let’s think about the third dose or it will be too late”
by Donatella Zorzetto
The decision of the FDA that is expected for today will not concern the other fragile sections of the population: it was discussed within the Biden administration to recommend the third dose also to those who are not transplanted or immunosuppressed, but the debate is still open as many immunologists do not believe that the scientific evidence gathered to date justifies a generalized third dose. Another unknown that will be resolved only at the end of the month concerns the Johnson & Johnson vaccine, which so far has been single-dose: the results of the clinical trial on the effectiveness of administering two doses are expected from the company, and this data may lead the Fda to evaluate an additional dose of this vaccine also for the immunosuppressed and transplanted groups.
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