Scientists closing in on why some people never get COVID. That could help with future vaccines

Early on in the pandemic, in 2021, Hugh Potter ate dinner and watched TV next to his wife while she coughed violently from COVID-19, yet he never even sniffled.

It's been thought that some people may not have gotten COVID because they were careful to avoid exposure. Alternatively, some people may have been infected but showed no symptoms. Another possibility is that some people have a genetic advantage that makes them a super-dodger.

"Bloody lucky," Potter, 68, said. "Where I work, I think almost everyone has had it." A few didn't believe the Pickering, Ont., resident has escaped it since the early years of the pandemic.

Now, experts peering into the genes of such rare people have gained some surprising insights.

Last week, scientists writing in the journal Nature described high activity of a specific gene in people who didn't get infected. And in a complementary research project, Potter provided DNA from saliva samples to researchers at McGill University Health Centre looking for those with a golden armour against the virus.

Researchers hope by better understanding early immune responses, it could help with developing nasal spray forms of vaccines for the coronavirus, similar to the existing FluMist to prevent influenza.

As much as people may wish to forget the pandemic emergency, the virus is still with us and kills about 20 people a week in Canada. The World Health Organization reported more than 2,600 new fatalities in April, bringing total confirmed cases to over 775 million including more than seven million deaths globally. 

To gain some leads into what makes people super-dodgers, in March 2021, investigators with the UK COVID-19 Human Challenge study administered a low dose of the original form of SARS-CoV-2 through the nose to 36 healthy adult volunteers and then closely tracked how long it took their immune cells to kick into gear. None were previously exposed to the virus or vaccinated.

The 16 participants with detailed monitoring of their blood and nose fell into three groups:

Christopher Chiu, a professor of infectious diseases at Imperial College London, and his co-authors saw high levels of activity in a gene called HLA-DQA2. They think the gene helps flag invaders to the immune system so it can quickly destroy the virus.

For medical researchers, the study offers a step-by-step look at what happens in the immune responses to the virus in both the nose and blood and their interaction.

Immunologists who weren't involved in the U.K. study say they're not sure why or how that specific gene offers protection.

"If you had asked me to bet money on the genes involved in the protection, they're not the ones I would have chosen," said professor Dawn Bowdish, who holds the Canada Research Chair in Aging and Immunity at McMaster University in Hamilton.

The realtor's motto of location, location, location applies, Bowdish said, because our nose, blood and lungs all differ in the type and timing of immune responses.