People vaccinated against Covid-19 who were infected with the first sub-variants of Omicron have four times the protection of those who received the vaccine but were not infected, a study published Wednesday indicates.
According to the scientific community, the Covid-19 pandemic seems to be passing from a hyperacute phase to an endemic phase. More importantly, it turns out that current Covid-19 vaccines are less effective in blocking infection with the Omicron variant than in blocking infection with previous variants. But the protection against serious diseases remains largely preserved.
Hence the primary interest of Covid-19 vaccines in providing long-term protection against the risks of hospitalization and death. It is therefore important that studies on Covid-19 vaccines and boosters evaluate not only short-term virus-neutralizing antibody loads, but also the duration of antibody responses, memory B cell responses and cellular responses.
It is in the context of this issue that a new study was presented this week which will be a reference on the subject. According to the Institute of Molecular Medicine (iMM), based in Portugal, it is one of the first studies in the world to analyze, in a group of vaccinated people, the probability of being infected by the sub-variant currently in circulation, BA.5, by estimating the degree of protection conferred by infections with previous variants.
It seems that “vaccinates who have been infected with the Omicron BA.1 and BA.2 subvariants have approximately four times the protection against infection with the BA.5 subvariant (in circulation since June) compared to vaccinates who have never been infected “, explained Luís Graça. principal researcher at IMM and full professor at the Faculty of Medicine of the University of Lisbon.
The study results were published Wednesday in the New England Journal of Medicine.
Still, according to the expert, the infections recorded in 2020 and 2021 from variants of ancestral strain, such as Alpha and Delta of SARS-CoV-2 “however, provide protection against infection with the new Omicron variant“, although it is not that high. Compared to those infected by the BA.1 and BA.2 variants, at the beginning of 2022.
“These results are very important because the adapted vaccines in clinical development and evaluation are based on the sub-variant BA.1, which was dominant in January and February 2022”Luís Graça emphasized.
The specialist, who is part of the Technical Commission for Vaccination against Covid-19 (CTVC) of the Directorate General of Health (DGS) in Portugal, points out that “These results show that protection is very important and above all they allow us to anticipate the benefit of appropriate vaccines” against Covid-19, added Luís Graça.