The reason why some people have not been infected with the virus that causes covid-19 in the more than two-year period of the pandemic intrigues scientists. Researchers at the University of Oxford investigated how genes can influence the body’s immune response and may have discovered important information to resolve this question.
The findings were published in the scientific journal Nature Medicine on October 13 and point to a gene that helps generate a stronger immune reaction after the two doses of the Covid-19 vaccine are administered. People who had HLA-DQB1*06, a variation of the HLA (Human Leukocyte Antigen) gene, had a higher antibody response than those without the gene.
In the UK, two in five people have this allele, and scientists have come to the conclusion that they are less likely to be infected with Sars-CoV-2 after being vaccinated than others. This would be because the HLA gene helps the immune system distinguish the body’s own proteins from proteins that are produced by viruses and bacteria.
The research provides evidence that genetic factors can cause the immune system to respond to Covid-19 vaccines differently in different people, but their clinical applications are still unclear.
“More work is needed to better understand the clinical significance of this association and, more broadly, what identifying this genetic variant can tell us about how effective immune responses are generated and how to continue to improve vaccines for all people.” Julian Knight, lead researcher on the study and professor of genomic medicine at the university’s Wellcome Center for Human Genetics, said in a statement.
Over the course of the research, the Oxford researchers analyzed DNA samples from 1,190 people who signed up for the university’s Covid-19 vaccine clinical trials; of 1,677 adults who were part of the study looking at second-dose options for those who had received Oxford-AstraZeneca or Pfizer-BioNTech immunizers as a first dose; and also from children who participated in clinical trials of the Oxford-AstraZeneca vaccine.
Individuals who carried the HLA-DQB1*06 gene had higher antibody responses 28 days after the first vaccine, and were more prone to this heightened immune reaction at any time after vaccination.
After a 494-day follow-up, the scientists found that while HLA-DQB1*06 was present in about a third of people who had symptoms of covid-19, it was present in 46% of individuals who reported no symptoms.
In other parts of the world, scientists are also trying to understand how genetics can explain why some people are more protected against Covid-19 than others, which could mean the same is true for other diseases and help in the development of new vaccines. and medicines.
At the Center for Human Genome and Stem Cell Studies (CEGH-CEL) of the São Paulo Research Foundation (Fapesp), researchers analyzed data from elderly people over 90 years old who recovered from the disease with mild symptoms. or who remained asymptomatic after testing positive for the new coronavirus.
The analysis indicated that those who had mild covid had more variants of the MUC22 gene, linked to the production of mucus and lubrication of the airways, which could mean that the gene reduces the active immune response against the virus while protecting the airways, increasing the individual resistance.
Scientists from Fapesp have also identified that the greater amount of an allele of the HLA-DOB gene may be related to a worsening of the infection. This gene is more common in African and South American people and can interfere with the passage of virus antigens to the cell surface, which alters the immune system’s ability to identify these antigens and provoke a response to them.
Raisa Toledo, special for Estadão