July 20, 2023 – It turns out that being a COVID-19 “super dodger” isn’t necessarily just luck. It’s genetics.
Scientists have discovered that many people who avoided COVID symptoms did get infected, but had a genetic mutation that trained the immune system to mount a supercharged response to the virus because it noticed similarities to the common cold.
The findings were published Wednesday in the journal Nature.
An estimated 20% of people infected with COVID don't have symptoms, prior research shows. This latest study found that people who carried a genetic mutation called HLA-B*15:01 were more than twice as likely not to have symptoms, compared to people in the study who didn’t have the mutation. The researchers called the HLA-B*15:01 mutation “common” and estimated that 1 in 10 people have it.
For the study, researchers used data from a bone marrow donor registry, since bone marrow matching also relies on HLA genetic information. They recruited 30,000 people from the bone marrow registry to use a mobile app developed by the University of California-San Francisco to track COVID status during the first year of the pandemic, when many people were doing routine COVID testing such as for work or due to potential exposure.
When the genetic mutation was identified among people who didn't have symptoms, another team of Australian researchers found that the mutation was linked to immune system T cells mounting a fast and effective response to SARS-CoV-2, the virus that causes COVID. The response suggested pre-existing immunity, such as an immune system that had been trained after responding to similar viruses.
The pre-existing immunity, which appeared to stem from the immune system’s memory of fighting off seasonal colds, was present even in people who hadn’t been vaccinated against or previously infected with SARS-CoV-2.
“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," researcher Stephanie Gras, PhD, a professor and laboratory head at La Trobe University in Australia, said in a statement.