However, questions remain about the prevalence of reinfection and the short- and long-term health effects that subsequent cases of the virus could have. With cases on the rise, here’s what experts have to say about the emerging evidence of reinfections.
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How likely are reinfections?
The emergence of the Omicron variant led to a tsunami of infections that saw the percentage of the population with antibodies to the virus rise from 7% to 45% between December 2021 and May 2022, according to an analysis published by COVID-19 Canada. Immunity Task Force this month. Story continues below ad Task force co-chair Kathryn Hankins said the jury is still out on how likely this previously infected population is to contract the virus again, particularly as Omicron’s BA.5 subvariant fuels a summer outbreak. “All we know is that it can happen,” said Hankins, a professor at McGill University. “This particular variant is actually capable of evading immunity, including immunity to its previous… sub-variant.” Prabhat Jha, a professor of epidemiology at the University of Toronto’s Dalla Lana School of Public Health, said early hopes that Omicron would act as a “benign natural recall,” spreading quickly but causing only mild symptoms, have not been sustained. “As more evidence accumulates, it suggests that Omicron is not the big protector we all thought it would be,” he said, citing data from the UK. 2:05 BA.5 variant soon to dominate Saskatchewan, Deputy CMHO says BA.5 variant soon to dominate Saskatchewan, says Deputy CMHO Lynora Saxinger, a professor in the University of Alberta’s department of medicine, said BA.5 is different enough from previous strains that immunity built up from a case of a previous variant may not prevent infection. Story continues below ad “It’s not impossible to get infected again,” he said.
How much protection do you get from “hybrid immunity”?
People who have been vaccinated and become infected should get a boost from “hybrid immunity,” Hankins said. However, signs that some people are reinfected with COVID-19 shortly after a previous bout suggest that any natural immune boost would be short-lived, he said. Trending Stories
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“People really shouldn’t think it’s done and dusted. They get it, and that’s it,” Hankins said. “You’ll get it again if you keep exposing yourself.” Saxinger said BA.5 may be even more adept at overcoming hybrid protection, but at this point, it’s unusual for people who have Omicron to be reinfected by one of its kin. “The combination of vaccination and relatively recent infection? not terrible against (BA.4 or BA.5,) especially if you don’t have any risk factors.” Canadian studies have shown that people with three COVID-19 vaccines and one infection have the highest antibody levels, Jha said. However, he stressed that people who are infected can benefit from another COVID-19 vaccine. “The evidence clearly says that counting on a natural infection to protect you is really dangerous. We knew that from the beginning,” he said. “The best protection is at least three doses of the vaccine.” Story continues below ad
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How does reinfection affect disease severity?
Hankins said it’s hard to pinpoint whether people, on average, get sicker the second or third time they get COVID-19. “It seems to vary a lot from person to person,” he said. “The general expectation would be that you wouldn’t be as sick the second time, but we see it all.” While governments report large numbers of people in the hospital — some of whom had the virus before — that may seem to suggest that reinfection leads to more severe disease, Saxinger said, that’s not necessarily the case. It’s just that there are more cases of COVID overall. “It’s really a function of just the sheer volume of transmission where we start to see increases in severe outcomes,” he said. “But on a per-person level, the risk of a serious outcome still seems to be quite low, especially if you’ve had a combination of being fully vaccinated and also being infected in the past.” Jha said this is another area where more study is needed. “But in theory, I have no doubt that having multiple infections is not good for you,” he said. Story continues below ad “Some riders say, ‘I’ll just get infected a few times and then I’ll be fine,’” he added. It’s also unclear, he said, whether re-infection increases that chance of long-term COVID infection. “There is a suggestion that multiple infections can contribute to greater symptoms. But again, that’s something we don’t know enough about.” 1:45 ER doctors urge people to get 4th dose of COVID-19 vaccine amid 7th wave ER doctors urge people to get 4th dose of COVID-19 vaccine amid 7th wave
What do we have to do?
“Everybody wants a quick answer and says, ‘OK, I want to know what to do.’ And I want to get it behind me,” Ja said. “But the virus works on its own schedule.” “Our immune system is trying to keep up with a mutated virus… And we basically have to be reasonable.” Story continues below ad Increasing uptake of the third dose is key to protecting people from reinfections, he said. Each shot you receive reduces the severity of the disease. National data show that only 56 per cent of Canadians aged 12 and over have had at least three doses of the COVID-19 vaccine, compared to about 90 per cent who have had two doses. Hankins agreed that getting a third shot is crucial. “It’s a highly infectious agent, but the more immunity you have on board, the better,” he said. © 2022 The Canadian Press
