People who get COVID-19 but don’t have any symptoms might be protected by a genetic mutation.
A new study offers the first evidence that genes influence a lack of symptoms for people with the virus, dubbed “superdodgers.”
A leukocyte antigen (HLA) is a protein marker that warns the immune system it is under attack.
Many superdodgers carry an HLA mutation, HLA-B*15:01, that helps the virus-killing T cells identify and attack COVID.
Vaccines could be updated in the light of HLA-B*15:01 variant’s effect, because the mutation means some bodies can spot coronavirus even if they’ve never come across it before, according to University College San Francisco.
The team claim their findings could “leverage” long-term public investment to protect against future pandemics.
By the UCSF’s calculation, the relatively common mutation is found in around 10 percent of the population.
It doesn’t stop the virus infecting cells, but it prevents people from developing any symptoms – including a runny nose or barely noticeable sore throat.
The team found 20 percent of participants who remained asymptomatic after testing positive had at least one copy of the HLA-B*15:01 variant.
Just nine percent of those who became sick had the mutation.
Those who carried two copies of the variant were over eight times as likely to avoid feeling poorly.
“If you have an army that’s able to recognize the enemy early, that’s a huge advantage,” saidProfessor Jill Hollenbach, a neurologist and epidemiologist at the American university. “It’s like having soldiers that are prepared for battle and already know what to look for, and that these are the bad guys.”
Prior to the study, researchers had suspected HLA was involved in whether symptoms emerged.
The team studied a national registry containing HLA data, collected to match bone marrow donors and recipients.
They used the university’s mobile app, the COVID-19 Citizen Science Study, to recruit nearly 30,000 bone marrow study participants and track them through the first year of the pandemic.
UCSF’s Professor Mark Pletcher, who researchers epidemiology and biostatistics, said: “We did not set out to study genetics, but we were thrilled to see this result come from our multidisciplinary collaboration with Dr. Hollenbach and the National Marrow Donor Program.”
Vaccines were unavailable at the time and many members of the public were routinely testing for the virus.
The final study group was limited to those who self-identified as white because there were too few respondents from other ethnic and racial groups.
Scientists identified 1,428 unvaccinated doctors who tested positive between February 2020 and April 2021, before vaccines were readily available.
Of the group, 136 remained asymptomatic for at least two weeks before and after testing positive.
HLA-B*15:01 was the only HLA variant with a strong link to symptom-free coronavirus.
Risk factors for severe COVID-19 – being older, overweight and having chronic diseases like diabetes – did not appear to affect asymptomatic cases.
Professor Stephanie Gras, a professor at La Trobe University, Australia, who partnered with UCSF on the research, said: “By studying their immune response, this might enable us to identify new ways of promoting immune protection against SARS-CoV-2 that could be used in future development of vaccine or drugs.”
The vice president of research at the National Marrow Donor Program Martin Maiers concurred, hoping the findings could form future public investment.
He said: “We are proud to partner on research that has the potential to leverage a long-term public investment in building the national registry to help cure diseases and improve our ability to avoid future pandemics.”
Produced in association with SWNS Talker