2023-07-24 09:15:00
A study claims that immunity found in 20% of the world’s population, unvaccinated, infected with Covid-19 but asymptomatic, would be linked to a certain type of antigens present in their bodies. This immunity would therefore be of a genetic nature.
Research had shown that 20% of people infected during the Covid-19 pandemic had no symptoms. A new study published on July 19 in the journal Nature hypothesizes that people carrying a particular genetic variant are twice as likely to be asymptomatic when they catch Covid-19. Those with two copies of this genetic variant are even eight times more likely not to get sick.
This study, however, only focuses on white participants who caught Covid early in the pandemic, before most of the current variants. The search does not include reinfections.
A specific antigen
By studying the human leukocyte antigens (HLA) of 30,000 volunteers who caught Covid, the researchers realized that 136 of them were asymptomatic despite not being vaccinated. One in five people in this group carried the HLA variant called “HLA-B*15:01”.
To understand the link between this antigen and Covid, the scientists looked at their T cells, which protect the body once morest their infections, but also on their T lymphocytes, which remember the viruses already encountered.
A link to the common cold
When they first caught Covid, their “HLA-B*15:01” variant T cells were particularly ready to replicate because these cells remembered other seasonal viruses that they had previously repelled.
Recent exposure to another coronavirus or the common cold might lead to fewer Covid symptoms for its people. A theory already proposed to understand why children have fewer serious symptoms of Covid. The researchers hope that this study can open up new treatments or vaccines in the future.
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