The reason why some people have not contracted the virus that causes Covid19 in the more than two years of the pandemic is intriguing scientists. Researchers at the University of Oxford have been studying how genes can affect the body’s immune response and may have uncovered important information that might help solve this question.
The findings, published October 13 in the journal Nature Medicine, point to a gene that helps generate a stronger immune response after two doses of the Covid19 vaccine have been administered. People with HLADQB1*06, a variation of the HLA (Human Leukocyte Antigen) gene, showed a stronger antibody response than people without the gene.
In the UK, two out of five people have this allele and scientists have concluded that they are less likely to contract SarsCoV2 than others after being vaccinated. This is because the HLA gene helps the immune system differentiate the body’s own proteins from proteins produced by viruses and bacteria.
Research provides evidence that genetic factors may cause the immune system to respond differently to Covid19 vaccines in different people, but their clinical applications remain unclear.
“Further work is needed to better understand the clinical significance of this association and, more generally, what the identification of this genetic variant can tell us about how effective immune responses are generated and how vaccines can be further improved for all people.” Julian Knight, lead Researchers on the study and a professor of genomic medicine at the university’s Wellcome Center for Human Genetics said in a statement.
The study
In the course of the research, the Oxford researchers analyzed DNA samples from 1,190 people who had enrolled in the university’s clinical trials of Covid19 vaccines; of 1,677 adults who participated in the study evaluating second dose options for those who received Oxford AstraZeneca or Pfizer BioNTech immunizers as their first dose; and also from children who participated in clinical trials of the OxfordAstraZeneca vaccine.
Individuals carrying the HLADQB1*06 gene showed stronger antibody responses 28 days after the first vaccination and were more susceptible to this enhanced immune response at any time point after vaccination.
After a 494day followup, the scientists found that while HLADQB1*06 was present in around a third of those with Covid19 symptoms, it was present in 46% of those who reported no symptoms.
In other parts of the world, too, scientists are trying to understand how genetics may explain why some people are better protected against Covid19 than others, which could mean the same is true for other diseases, and could help in the development of new vaccine medicines .
At the Center for Human Genome and Stem Cell Studies (CEGHCEL) of the São Paulo Research Foundation (Fapesp), researchers analyzed data from elderly people over the age of 90 who recovered from the disease with mild symptoms or remained asymptomatic after testing positive for the new coronavirus.
The analysis showed that those who had mild Covid had more variants of the MUC22 gene linked to the production of mucus and airway lubrication, which could mean that the gene reduces the active immune response against the virus and at the same time protects the airways, reducing the individual resistance.
Fapesp scientists also found that the greater abundance of one allele of the HLADOB gene could be linked to a worsening of the infection. This gene is more common in people in Africa and South America and can disrupt the passage of viral antigens to the cell surface, altering the immune system’s ability to identify and mount a response to those antigens.
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