Genetic link to asymptomatic COVID: Study

Michelle Wisbey

20/07/2023 4:48:53 PM

Landmark research finds gene variants and exposure to the common cold could help develop more impactful COVID-19 medications.

Microscopic image of COVID-19 virus
More than 68 million vaccine doses have so far been administered in Australia since February 2021.

Scientists have discovered a genetic link to asymptomatic COVID-19, with hopes it could be the first step to improved vaccines and treatment in clinical practice.  
The US-Australian study also found that for those with the genetic variant, exposure to seasonal colds and other coronaviruses helped develop this lack of symptoms.
‘It’s like having soldiers that are prepared for battle and already know what to look for and can tell by the uniform that these are the bad guys,’ the report said.

While Australian COVID-19 rates have dropped dramatically, last week alone, 119 people died of the virus and 1871 people were being treated in hospital.
Lead researcher Professor Stephanie Gras, from La Trobe University, told newsGP the findings represent an exciting breakthrough.
‘The primary focus of the research was to provide some antiviral treatment that’s safe for people so we can try to return to a normal life,’ she said.
Published in Nature, the study investigated the genetics of almost 30,000 registered bone marrow donors.
It found of 1428 unvaccinated donors with positive test results for SARS-CoV-2, and of the 136 who had no symptoms, 20% carried the gene variant, HLA-B15 (human leucocyte antigens).

They also discovered that those who carry one copy of the protective gene are twice as likely not to show symptoms, and those who carry two copies are eight times more likely to be asymptomatic.
In the study’s second phase, researchers examined samples taken before the pandemic, finding T-cells reacted to some fragments of COVID-19 in people with the gene variant who had never had the virus.
Those people were also found to have a stronger immune response to viruses which can cause infections such as the common cold.
‘The fact that people who carry the HLA-B15 gene have high levels of pre-existing memory T-cells that recognise SARS-CoV-2 would mount a faster and stronger immune response after infection, and likely to eliminate the virus quickly,’ the study said.  
More than 68 million vaccine doses have so far been administered in Australia since the COVID-19 vaccination program began in February 2021, and around 74,000 doses have been administered over the past seven days.
While it is hoped the new research could help to create more effective vaccines in the future, Professor Gras warned there is still a lot of work ahead before those treatments are rolled out.
‘What we want to do is to pinpoint which of those T-cells are the best ones and which part of the virus we need to use if we are to make new vaccines,’ she said.
‘There are more likely other HLA molecules and other types of molecules that will also work to protect individuals, and so if we understand which molecules they are, we can actually create better vaccines.’
University of Queensland Associate Professor of Medicine, Paul Griffin told newsGP the research confirms responses to COVID-19 can be ‘vastly different in different people’.
‘We always have to remember that when information like this comes to us it’s early days, so it doesn’t mean we’re at the stage where we can have personalised vaccines or treatment,’ he said.
‘This is a really big first step into getting some kind of understanding about people’s genetic susceptibility, or their ability, to be protected against more severe disease.’
He also said moving forward, funding will be key for maintaining research momentum.
‘One thing that is a bit of a concern [is] that as people move on from being worried about COVID, funding for research and the resources to make these important discoveries might start to dry up,’ Associate Professor Griffin said.  
‘We do need to make sure the focus stays on COVID because it isn’t going to go away by itself.’
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