HAVE the effect of an armor, a shield against Covid in its various variants, even those of the most recent appearance. Two doses of the vaccine, on the immunosuppressed who have contracted the virus and are cured, even after some time, promise efficacy and resistance that can reach maximum levels. Even among those who had never known those mutations of the virus. The study, published in Random Journal of the European Society for Medical Oncology, developed by researchers at the San Matteo Polyclinic in Pavia, in collaboration with the Guglielmo Da Saliceto hospital in Piacenza, not only justifies the third dose of vaccine on the most fragile patients, but goes further, explaining that there is a hitherto unimagined level of immunity in those who developed the disease, even if several months ago.
The researchers started from a basic question: what effect does the vaccine have on the immunosuppressed? From there a series of checks carried out by the medical teams of the two hospitals. The study was carried out on 88 patients, some of whom recovered from Covid as early as last spring, being treated with immunotherapy drugs. “The goal – he explains Fausto Baldanti, head of the Molecular Virology laboratory of San Matteo – was to prove the efficacy and safety of a complete course of vaccination against Covid. The preliminary results are encouraging and in some ways surprising. Vaccination was effective in stimulating the response against the virus in the vast majority of patients with cancer even during treatment. In fact, all patients who contracted a previous Sars-Cov-2 infection developed antibody and cell-mediated responses already after the first dose “.
But it is with the recall that, according to the researchers, the qualitative leap has been made. “After the second vaccination dose, in those recovered from Covid we found median levels of antibody response much higher than in the” naïve “patients, ie those who did not contract the virus”. In practice: 26 times more for the total IgG levels, 6 times more for the neutralizing titers and 4 times for the T-cell response levels. “In patients” naïve “for Sars-CoV-2 infection, the antibody response (both total IgG and neutralizing antibodies) after the first dose of vaccine was 44%, and rose to 96% after the second – continues Baldanti – while the cell-mediated response was detectable in 67% of patients after the first dose and in 90% after the second “.
The researchers therefore observed that “the major response is achieved only after the second dose and suggest that triple exposure to the antigenic stimulus, ie the third dose of vaccine, can significantly strengthen the vaccine response in frail patients”.
The data, therefore, say that even frail patients can achieve a high degree of “shielding” from the virus after the vaccine, and “that levels of protection are gained after the booster”. There remains a 10% who have an incomplete answer, so much so that they deserve the definition of “non responders”. “We are talking about people who, for example, can only have the antibody response and not T-cellular and therefore remain at risk of contagion – underlines the virologist – these data suggest that the strategy of a third dose in fragile subjects is more than justified because it consolidates optimal effect of the vaccine. At the same time they prove that a person cured and then vaccinated is overprotected. Because the patients we examined were all vaccinated in the spring, when the Delta variant was not there. But, surprisingly, when we put the their serum in contact with the Delta neutralized it “.
His Lancet studied it
However, a study on Lancet warns that this is not always the case. Basically it says: the third dose is fine on frail people, but it is not proven that those who have had a limited response with the first two doses can develop a higher one with the third. In conclusion, the scholars argue that to date there is no scientific evidence for a further recall on the entire population. The analysis is signed by an international group of scientists: among these also some members of the WHO (World Health Organization) and the American FDA (Food and drug administration). According to the team of researchers, the current coverage is sufficient even in severe Covid cases and has also proved adequate to counter the Delta variant.
The study examines dozens of research published in international journals. What emerges is that Covid-19 vaccines continue to be extremely effective against serious disease, including variants. By averaging the results reported by the research, vaccination was 95% effective against severe SARS-CoV-2 disease, due to both the Delta and Alpha variants, and over 80% effective in protecting against any infection with these variants. In the presence of the different variants that we know, the effectiveness of the vaccine is greater against severe disease, while it is a little less effective for countering asymptomatic forms of coronavirus or the transmission of infection. It was also concluded that, in populations with high vaccination coverage, the unvaccinated minority is still the main transmission factor, as well as being themselves at the highest risk of serious disease.
So everyone has to be vaccinated, the researchers conclude. Explaining: “Taken together, the currently available studies do not provide sufficient evidence of a substantial decline in vaccine protection against severe disease, and therefore hospitalization, which is the primary goal of vaccination.” While some gain may eventually be gained from the third dose, the benefits of providing protection to all who have not yet or are not fully vaccinated will never be outweighed. “If vaccines were distributed where they would do best, they could accelerate the end of the pandemic by inhibiting the further evolution of the variants,” explains the research coordinator. Ana-Maria Henao-Restrepo, WHO.
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