A family member was coming to the hospital with their loved one who was having difficulty breathing or was connected to a ventilator. But instead of getting sick as well, this person seemed to have somehow avoided the virus altogether. “Wait a minute. You live in the same house, in the same bed, you do everything together – he is in the ICU and you are not?” said Dr. Donald Vinh, an infection specialist and medical microbiologist at McGill University Health Center. “It became very clear that there were people who were exposed without getting seriously ill,” Vinh recalls, but the “burning question” was, did they just have no symptoms or escape the infection? And if so, how? The sixth wave brought a COVID outbreak to some communities in Ontario, including Toronto, with many, many more friends and family members getting sick than ever before in the pandemic. But for every story someone out with the virus, it seems like there is someone else who survived, despite the exposure, or even lives in the same house with many people who tested positive. If you’ve bypassed COVID so far, you probably have vaccines, masks and luck on your side, experts say. There is, however, a very small group of people who seem to have innate immunity to the virus. There is in fact a precedent for this with other diseases, and Canadian researchers hope that unlocking the mystery of these “COVID resistances” may help develop more effective treatments and vaccines. For the average person who is not infected, “it ‘s probably because you’re doing all the right things for public health,” said Dawn Bowdish, Canada’ s research and aging professor and professor of medicine at McMaster University. There are people out there, however, probably less than one percent of the population, says Bowdish, who are “highly exposed but seropositive” – health care workers, for example, who were in COVID wards without proper masks before from vaccines. Unlike people who got it and were asymptomatic, this elite group never developed antibodies in their blood for the virus (and scientists can tell if these antibodies are from the disease or the vaccine), having some kind of natural immunity. Bowdish is leading a large study of COVID in long-term care and speculates that some people may have developed immunity after repeated exposure to other seasonal coronaviruses that cause the common cold. “When exposed to SARS-CoV-2 they increase this immune response and help in some way protect themselves,” he said. “Ninety-nine points, nine percent of us, we have to rely on our antibodies to do some of this work, while these other people use what we call T-cells” – another part of the immune system – who have seen a lot. similar months or years ago and “go into action and clear it up before it even starts”. McGill’s Vinh is the leader of the Canadian website for an international study examining so-called “COVID resistors” that began as an attempt to determine why some people have a severe disease crisis. The team identified approximately 700 eligible individuals worldwide as exposed, negative (by polymerase chain reaction (PCR) or rapid testing) and never developed antibodies. “We are looking for the genetic basis for why humans are resistant to COVID infection,” Vinh said. “If we can really understand the molecular basis by which humans are naturally resistant to infection, this first step, when the virus tries to enter our cells, can reasonably and rationally guide the development of therapies,” he added. If you are still convinced that you belong to this tiny elite group, Vinh and his team are still actively recruiting for their study. In Britain, a research team went one step further in what is called a human challenge study, deliberately exposing 36 healthy, young, unvaccinated adults to the virus. The main goal was to find the infectious dose required for the infection, but they also found that “it is interesting that 50 percent of the volunteers were not infected,” said Dr. Andrew Catchpole, chief scientist at hVIVO, the company that conducted the study. . was recently published in Nature Medicine, in collaboration with Imperial College London and the British Government. Although they never expected everyone to become infected when using low doses, they are currently studying the immune responses of those who became infected versus those who were not infected in the hope that this could help them find future drugs, he added in an email. “After two years of ‘information in the dark’ with treatments, the idea with this kind of work is to start something that is already happening to people and get out of there,” Vinh said. “Some people say, well it’s not a bit drawn, it’s, other than what science is supposed to be, it’s supposed to be drawn,” he said. “But it is not unproven.” Hundreds of years ago, when the plague decimated Europe, there were cases of people who simply never got it, even though they sometimes lost their entire families to the disease. One theory is that people who survived the Black Death had a “specific mutation in one of the cells of their immune system that made them less likely to support the bacteria that caused the plague,” said McMaster Bowdish. Another famous example is a group of sex workers in Nairobi, Kenya who have been exposed to HIV many times but have never been infected. The message for most people who have avoided COVID so far is not to rely on this innate immunity as a kind of hidden superpower, Bowdish added. “But I think the inspiration for finding people like him is that it gives vaccine immunologists a clue as to what they should target.” Her colleagues at McMaster, for example, are working to develop an inhaled vaccine that would ideally provide broader immunity to multiple variants of COVID, rather than fighting to develop a specific vaccine each time the virus is mutated. “In a perfect world, our vaccines would do exactly what these people naturally do, they would rule out the infection before it even started and you would never pass it on and you would never transmit it,” Bowdish said. “And we could all go back to our 2019 life.” May Warren is a Toronto-based breaking news reporter for the Star. Follow her on Twitter: @ maywarren11
