Covid-19: Vaccinated people infected with Omicron are better protected against new variants

According to the scientific community, the Covid-19 pandemic is moving from an epidemic phase to an endemic phase. But after all, it turns out that current Covid-19 vaccines are less effective at preventing infection with the omicron variant than they were at preventing infection with earlier types. But protection against serious diseases is often preserved.

Hence, the primary interest of anti-Covid-19 vaccines is in providing long-term protection against increased 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 assess antibody responses, memory B cell responses, and the duration of cell responses.

A new study was published this week against the backdrop of this issue, which may be a reference on the matter. According to the Portugal-based Institute of Molecular Medicine (iMM)., This is one of the first studies in the world to analyze the probability of infection by assessing the degree of protection conferred by infections with previous variants of the currently circulating subtype BA.5 in a group of vaccinated individuals.

It seems that “Vaccines infected with the Omicron BA.1 and BA.2 subtypes have approximately four times the protection against infection with the BA.5 subvariant (circulating since June) than vaccines that have never been infected.”, explained by Luis Graça. Principal Researcher 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.

However, according to the expert, the infections recorded in 2020 and 2021 were caused by ancestral lineages such as alpha and delta of SARS-CoV-2. “However, provide protection against infection with the new Omicron variant“, although it is not higher, compared to those affected by categories BA.1 and BA.2, at the beginning of 2022.

“These results are particularly important because the adapted vaccines in clinical development and evaluation are based on the BA.1 subtype, which predominated in January and February 2022”Soul Luis Graça.

The expert who is part of the Technical Commission for the Vaccine against Covid-19 (CDVC) of the Public Health Directorate (DGS) in Portugal points out. “These results show that protection is very important, above all to expect the benefit of appropriate vaccines” Against Covid-19, Louis added Grassa.