In two years of the pandemic, they have never caught the virus responsible for COVID-19. Some have managed the pandemic particularly tightly, given their state of health, but others, not at all. How to explain it? If few answers are still known, an international study on these “resistant to infection” tries to elucidate the mystery.
Posted at 7:00 p.m.
“A bit of a joke with my friends, they said that I was invincible to COVID-19. Almost everyone around me had it, but not me, ”launches Laurence Taschereau.
Despite COVID-19, for the past few months, the young student has continued to go to her classes every day, also frequently seeing friends, relatives and co-workers. At the height of the fifth wave, her roommate even caught the virus, but nothing helped.
“We had made the decision that I was going to stay in the apartment with her, for at least a week. I remember I was like, “Finally, I’m going to have it.” That week, I did at least four rapid tests, and it was always negative. I never had any symptoms either, ”says the student, who admits, however, that she was never able to confirm her diagnosis with a PCR test, like most Quebecers. “Apart from a few sore throats, I don’t think I’ve even had the flu in my life,” she adds, saying she doesn’t know why she’s “resistant” to viruses in general.
PHOTO ROBERT SKINNER, THE PRESS
Laurence Taschereau, who lives in Rosemont–La Petite-Patrie
Understanding “the genetic basis”
The case of Laurence Taschereau is far from unique, in Quebec and around the world. “There are people who seem very exposed and who, for all the reasons, should be infected. Yet they took tests for COVID, and they were always negative. This suggests that they are not infected or, perhaps more accurately, that they are resistant to infection,” says Dr.r Donald Vinh, infectiologist-microbiologist at the McGill University Health Center.
Along with several other researchers, he is participating in the study of the international consortium COVID Human Genetic Effort. His goal and that of his colleagues is simple: “to understand the genetic and molecular basis of this apparent resistance”.
One thing remains certain from the outset: “The virus must attach itself and enter our cells – this is the infection stage – after which it may or may not cause serious illness”, explains the Dr Vinh. His group therefore first “identified the molecular basis that explains why some people develop severe COVID after infection, while others do not”. “We are also investigating the molecular basis of other manifestations of COVID, such as the multi-inflammatory syndrome seen in children and adults,” he says.
PHOTO EDOUARD PLANTE-FRÉCHETTE, THE PRESS
Donald Vinh, infectiologist-microbiologist at the McGill University Health Center
To achieve this, the experts are looking more specifically for people “who have been significantly exposed” to COVID-19 without being infected, for example by having been in contact with a family member or a roommate declared positive. As part of the study, preference is given above all to unvaccinated subjects, who would in theory have an even greater risk of having the disease.
“In these people, we will perform different immunological tests to confirm that their immune system has never seen COVID, that is, they have never been infected. These people can be resistant to the disease, and we will determine if there is a genetic basis for their resistance”, illustrates Donald Vinh.
Never affected by the virus
Montrealer Raphaël Young has also been spared the virus so far. “The first year, like everyone else, I was really careful. But this year, I found my friends, I went to shows, I was exposed to masses of people. We can say that with the last two variants, I paid less attention. But I never had any symptoms or positive tests,” he says.
Like Laurence, Raphaël was also directly exposed to the virus, when his spouse, with whom he lives, contracted it. “I was really surprised at that, because it was direct exposure, but all the antigen tests I had came back negative. And I never felt anything. I think it’s possible that I was asymptomatic at some point, ”he says.
Suffering from cystic fibrosis, Nathalie Montpetit, for her part, has been managing her social contacts very tightly since the start of the pandemic. “Since March 7, 2020, I have had to leave my house eight times, for my vaccines, for a hospital appointment, and once to vote. The rest of the time, I stay on my turf. For me, the virus can be very dangerous,” she says.
PHOTO PROVIDED BY NATHALIE MONTPETIT
Nathalie Montpetit has cystic fibrosis.
“A lot of people don’t realize that when you have a weakened immune system, you don’t take this virus like the flu, like something that can shut you down for a few days. Me, if I never had the virus, it’s because I was really very careful, ”concludes Mme Montpetit.
No government study
At the Ministry of Health and Social Services (MSSS), spokesperson Marjorie Larouche confirms that the government “is not conducting a study” on those resistant to COVID-19 for the moment, preferring to let international researchers establish certain great paradigms. “However, our experts constantly monitor the available scientific data,” she says.
Professor and researcher specializing in immunology and virology at the National Institute for Scientific Research (INRS), Alain Lamarre recalls, however, that the immune control of COVID-19 is “an incredible source of scientific research”, because very few answers are still known.
“Understanding the phenomenon of elite controllers, in English, it would be something quite big. I hope that one day we will be able to explain how people are able to resist exposure to a virus that is nevertheless very contagious, ”he concludes.