In the early dark days of the pandemic, when even then sometimes referred to as the novel coronavirus vaccines were just a hope, researchers around the world began to notice a strange phenomenon.
A family member would come to the hospital with a loved one who was struggling to breathe, or was attached to a ventilator. But instead of getting sick, this person somehow dodged the virus completely.
“Wait a minute. You live in the same house, in the same bed, you do everything together – he’s in the ICU and you’re not?” An infectious disease specialist and medical microbiologist at McGill University Health Center, Dr. Donald Vinh said.
“It became very clear that there were people who were exposed without serious illness,” Vinh recalls, but the “burning question” was, did they not have symptoms, or did they survive the infection? And if so how?
The sixth wave has brought an explosion of COVID-19 to some Ontario communities, including Toronto, with many, more friends and family members getting sicker than ever in the pandemic.
But for every story of someone out there with the virus, it seems that someone else who was spared despite a risk, or even several people living in the same household, tested positive. Experts say that if you have cracked COVID by now, you probably have vaccines, masks and luck.
However, there is a very small group of people who have an innate immunity to the virus. There is indeed a precedent for this with other diseases, and Canadian researchers hope that unlocking the mystery of these “COVID resistances” could help develop more effective treatments and vaccines.
For the average person who hasn’t been infected, “it’s probably because you’re doing all the right public health things,” said Don Boudish, Canada Research Chair in Aging and Immunity and professor of medicine at McMaster University.
There are people, however, perhaps less than one percent of the population, Boudish estimates, who are “highly exposed but seronegative” – health care workers, for example, who were in COVID wards without proper masks before the vaccine. Unlike individuals who got it and were asymptomatic, this elite never developed antibodies to the virus in their blood (and scientists can tell whether those antibodies are from the disease or from the vaccine), some sort of virus. Have natural immunity.
Bodish is a co-lead on a large study about COVID in long-term care and speculates that some individuals may have developed immunity after repeated exposure to other seasonal coronaviruses that cause the common cold. causes are made.
“When they are exposed to SARS‑CoV‑2, they amplify that immune response, and help protect themselves,” she said. “Ninety-nine-point-nine percent of us, we have to rely on our antibodies to do that job, while these other people use T-cells”—another part of the immune system—that saw some great Same months or years ago and “jump in on the task and clean it up before you even start.”
Canadian Site Leads to an International Inquiry Looking at McGill’s Vinh So-called “Covid Resistant” It began as an attempt to determine why some people suffer severe illness. The team has identified nearly 700 people worldwide who qualify as exposed, test negative (with polymerase chain reaction (PCR) or rapid tests) and never developed antibodies.
“We are looking for the genetic basis of why people are resistant to COVID infection,” Vinh said.
“If we can truly understand the molecular basis by which humans are naturally resistant to infection, then the first step, when the virus tries to get into our cells, can logically and rationally guide the development of therapies.” can do,” he said.
If you’re still convinced that you’re one of this small elite group, Vinh and his team are still actively recruited for their study.
In the UK, a research group has taken this a step further in the Human Challenge Study, where they intentionally exposed 36 healthy, young unvaccinated adults to the virus. The main objective was to find the infectious dose required for infection, but they also found that “interestingly, 50 percent of the volunteers did not become infected,” said Dr. Andrew Catchpole, chief scientist at hVIVO, the company that conducted the study, recently. Published in Nature Medicine in partnership with Imperial College London and the British Government. Although they never thought that everyone would become infected if low doses were used, they are currently studying the immune responses of people who did not become infected in the hope that it could lead to future drugs. Might help find it, he added in an email.
Vinh said that after two years of “shots in the dark” with treatments, the idea with this kind of work is to start with something that’s already happening in humans and go from there.
“Some people say it’s not a little far-fetched, it is, except what is considered science is considered far-fetched,” he said. “But it’s not unproven.”
Hundreds of years ago when the plague was ravaging Europe, there were cases of people who never got it, despite sometimes losing their entire families to the disease.
One theory is that those who survived the Black Death “had a specific mutation in one of their immune cells, which made them less likely to support the bacteria that cause the plague,” McMaster’s Boudish said. Another famous example is a group of sex workers in Nairobi, Kenya who were exposed to HIV several times but never got infected.
Boudish said the message for most people, who have so far avoided COVID, is not to rely on this innate immunity as some sort of hidden superpower. “But I think the inspiring part about finding people like this is that it gives the immunologists who are making the vaccines a clue about what they should be targeting for those people.”
His colleagues at McMaster, for example, are working on developing an inhaled vaccine that would ideally provide broad immunity against multiple types of COVID, rather than having to develop a specific vaccine each time the virus mutates. To run.
“In an ideal world, our vaccines would do exactly what these people do naturally, stop that infection before it even starts and you would never get it and you would never transmit it,” Boudish said. . “And we will all be able to go back to our 2019 lives.”