Covid positive but no symptoms? The reason probably lies in your genes. Here's how

Edited By: Sneha Swaminathan
Washington DC Updated: Jul 20, 2023, 11:42 AM(IST)

Scientists have now made a significant discovery, identifying a genetic mutation associated with a higher likelihood of evading symptoms during a COVID-19 infection. (Wikimedia Commons) Photograph:( Others )

Story highlights

The detected mutation seems to provide a benefit to the immune cells of people who have been exposed to 'seasonal' coronaviruses, the ones responsible for causing common colds.

Around 20 per cent of individuals who contract the SARS-CoV-2 coronavirus experience no symptoms of the illness.

Scientists have now made a significant discovery, identifying a genetic mutation associated with a higher likelihood of evading symptoms during a COVID-19 infection, according to the Nature Journal.

The identified mutation appears to confer an advantage to the immune cells of individuals who have previously encountered 'seasonal' coronaviruses, responsible for causing the common cold.

This advantage allows the immune system to more efficiently detect and eliminate the SARS-CoV-2 virus before it can trigger an overwhelming immune response.

Jill Hollenbach, an immunogeneticist from the University of California, San Francisco, who co-authored the study, told the Nature Journal that this mutation enables immune cells to act proactively against the pathogen.

Also read | COVID-19: China deletes mortality data that offered a peek into impact of its pandemic policies

Acclaim for the research and its scope

Experts in the field have applauded the research findings.

Jean-Laurent Casanova, a paediatric immunologist from Rockefeller University, praises the study, acknowledging it as the most significant association between a common gene and COVID-19 to date.

While studies exploring the link between genetics and severe COVID-19 cases are essential, Hollenbach emphasises that most SARS-CoV-2 infections result in mild symptoms, making the investigation of asymptomatic cases crucial.

To identify individuals with asymptomatic infections, the researchers examined a database of bone-marrow donors, enrolling nearly 30,000 participants.

Of the 1,400 participants who tested positive for SARS-CoV-2 during the 15-month study, 136 remained asymptomatic.

The scientists then focused on variations in HLA genes, responsible for encoding proteins found on the surface of cells that play a vital role in the immune response.

Also read | United States cuts off funds to Wuhan Institute over Covid stonewalling: Report

Strong link between HLA mutation and asymptomatic infections

The study revealed a strong link between asymptomatic infections and a specific HLA mutation carried by approximately 10 per cent of the study's population.

Individuals with the mutated gene were twice as likely to remain asymptomatic compared to those without it, and those with two copies of the gene were eight times as likely. The researchers were surprised by the magnitude of this effect.

Also watch | WHO accuses China of under-representing COVID-19 death figures

The main analyses were conducted on participants who identified as white, as there were insufficient numbers from other ethnic and racial groups for a comprehensive analysis.

However, evidence suggests a link between the mutation and asymptomatic infections in Black individuals, though results for Asian and Hispanic individuals were less conclusive.

The discovery of this "smoking gun" variant opens new possibilities for next-generation COVID-19 vaccines. These vaccines could not only reduce disease severity but also prevent symptomatic infections, potentially making a significant impact on curbing the spread of the virus.

 

WATCH WION LIVE HERE:

Read in App