People who have been vaccinated against Covid-19 and have contracted the first subvariants of Omicron have four times more protection than those who received the vaccine but were not infected, a study published Wednesday shows.
According to the scientific community, the Covid-19 pandemic appears to be moving from a hyperacute phase to an endemic phase. Most importantly, it turns out that the current Covid-19 vaccines are less effective at blocking infection with the Omicron variant than at blocking infection with the earlier variants. However, protection against serious illnesses is largely retained.
Therefore, the primary interest of anti-Covid-19 vaccines is to provide long-term protection against the risks of hospitalization and death. Therefore, it is important that studies of Covid-19 vaccines and boosters not only assess short-term virus-neutralizing antibody loads, but also the duration of antibody responses, memory B-cell responses, and cellular responses to cross-reacting T-cells.
In connection with this issue, a new study was presented this week, which will serve as a reference in this matter. According to the Institute of Molecular Medicine (iMM), based in Portugal, This is one of the first studies in the world to analyze the likelihood of infection with the currently circulating subvariant BA.5 in a group of vaccinates by estimating the level of protection from infection with earlier variants.
Apparently “Vaccinated individuals who have been infected with subvariant Omicron BA.1 and BA.2 have about four times the protection against infection with subvariant BA.5 (circulating since June) than vaccinated individuals who have never been infected .”, explained Luís Graça. Principal Investigator at IMM and Full Professor at the Faculty of Medicine, University of Lisbon.
The results of the study were published Wednesday in the New England Journal of Medicine.
Nevertheless, according to the expert, the infections recorded in 2020 and 2021 by ancestral lineage variants such as alpha and delta of SARS-CoV-2 “but provide protection against infection with the newer Omicron variant”, albeit not as high. Compared to people infected with BA.1 and BA.2 variants in early 2022.
“These results are very important because the adapted vaccines that are in clinical development and evaluation are based on the BA.1 subvariant that was dominant in January and February 2022,” stressed Luís Graça.
The specialist, who is part of the Technical Commission for Vaccination against Covid-19 (CTVC) of the General Directorate of Health (DGS) in Portugal, emphasizes that “these results show that protection is very important, that above all they make it possible , anticipating the benefit of appropriate vaccines against Covid-19, added Luís Graça.