Grandparents killed in wrong-way crash on Hwy. 401 identified
A 60-year-old man and a 55-year-old woman killed in a wrong-way crash on Highway 401 earlier this week have been identified by the Consulate General of India in Toronto.
The idea of waning immunity has picked up steam in recent weeks, with some countries using it to justify rolling out third-dose COVID-19 vaccine boosters to their populations. But immunologists say the concept has been largely misunderstood.
While antibodies -- proteins created after infection or vaccination that help prevent future invasions from the pathogen -- do level off over time, experts say that's supposed to happen.
And it doesn't mean we're not protected against COVID-19.
Jennifer Gommerman, an immunologist with the University of Toronto, said the term "waning immunity" has given people a false understanding of how the immune system works.
"Waning has this connotation that something's wrong and there isn't," she said. "It's very normal for the immune system to mount a response where a ton of antibodies are made and lots of immune cells expand. And for the moment, that kind of takes over.
"But it has to contract, otherwise you wouldn't have room for subsequent immune responses."
Antibody levels ramp up in the "primary response" phase after vaccination or infection, "when your immune system is charged up and ready to attack," said Steven Kerfoot, an associate professor of immunology at Western University.
They then decrease from that "emergency phase," he added. But the memory of the pathogen and the body's ability to respond to it remains.
Kerfoot said B-cells, which make the antibodies, and T-cells, which limit the virus's ability to cause serious damage, continue to work together to stave off severe disease long after a vaccine is administered. While T-cells can't recognize the virus directly, they determine which cells are infected and kill them off quickly.
Recent studies have suggested the T-cell response is still robust several months following a COVID-19 vaccination.
"You might get a minor infection ... (but) all of those cells are still there, which is why we're still seeing very stable effectiveness when it comes to preventing severe disease," Kerfoot said.
A pre-print study released this week by Public Health England suggested protection against hospitalization and death remains much higher than protection against infection, even among older adults.
So the concept of waning immunity depends on whether you're measuring protection against infection or against severe disease, Kerfoot said.
Ontario reported 43 hospitalized breakthrough cases among the fully vaccinated on Friday, compared to 256 unvaccinated hospitalized infections. There were 795 total new cases in the province that day, 582 among those who weren't fully vaccinated or had an unknown vaccination status.
British Columbia, meanwhile, saw 53 fully vaccinated COVID-19 patients hospitalized over the last two weeks, compared to 318 unvaccinated patients.
"You'll hear people say that vaccines aren't designed to protect infection, they're designed to prevent severe disease," Kerfoot said. "I wouldn't say necessarily it's the vaccine that's designed to do one or another ... that's just how the immune system works."
Moderna released real-world data this week suggesting its vaccine was 96 per cent effective at preventing hospitalization, even amidst the more transmissible Delta variant, and 87 per cent effective at preventing infection -- down from the 94 per cent efficacy seen in the clinical trials last year.
Moderna CEO Stephane Bancel said that dip "illustrates the impact of waning immunity and supports the need for a booster to maintain high levels of protection."
Pfizer-BioNTech has argued the same with its own data, and an advisory panel to the U.S.-based Food and Drug Administration voted Friday to endorse third doses for those aged 65 and older, or at high risk for severe disease.
However, the panel rejected boosters for the general population, saying the pharmaceutical company had provided little safety data on extra jabs.
Gommerman said the efficacy data presented by Moderna doesn't signal the need for a third dose.
"The fact it protects 87 per cent against infection, that's incredible," she said. "Most vaccines can't achieve that."
Bancel said Moderna's research, which has yet to be peer reviewed, suggested a booster dose could also extend the duration of the immune response by reupping neutralizing antibody levels.
But Dr. Sumon Chakrabarti, an infectious physician in Mississauga, Ont., said looking solely at the antibody response is misleading, and could be falsely used as justification for an infinite number of boosters.
Israel, which has opened third doses for its citizens, recently talked about administering fourth doses in the near future.
"This idea of waning immunity is being exploited and it's really concerning to see," Chakrabarti said. "There's this idea that antibodies mean immunity, and that's true ... but the background level of immunity, the durable T-cell stuff, hasn't been stressed enough."
While some experts maintain boosters for the general population are premature, they agree some individuals would benefit from a third jab.
The National Advisory Committee on Immunization has recommended boosters for the immunocompromised, who don't mount a robust immune response from a two-dose series.
Other experts have argued residents of long-term care, who were prioritized when the rollout began last December, may also soon need a third dose. The English study suggests immunity could be waning in older groups but not much -- if at all -- among those under age 65.
Chakrabarti said a decrease in protection among older populations could be due more to "overlapping factors," including their generally weaker immune systems and congregate-living situations for those in long-term care.
"These are people at the highest risk of hospitalization," he said. "Could (the length of time that's passed following their doses) be playing a role? Yeah, maybe."
While we still don't know the duration of the immune response to COVID-19 vaccination, Gommerman said immune cells typically continue to live within bone marrow and make small amounts of antibodies for "decades."
"And they can be quickly mobilized if they encounter a pathogen," she said.
This report by The Canadian Press was first published Sept. 19, 2021.
A 60-year-old man and a 55-year-old woman killed in a wrong-way crash on Highway 401 earlier this week have been identified by the Consulate General of India in Toronto.
Three people have been arrested and charged in the killing of B.C. Sikh activist Hardeep Singh Nijjar – as authorities continue investigating potential connections to the Indian government.
Pius Suter scored with 1:39 left and the Vancouver Canucks advanced to the second round of the NHL playoffs with a 1-0 victory over the Nashville Predators on Friday night in Game 6.
TD Bank Group could be hit with more severe penalties than previously expected, says a banking analyst after a report that the investigation it faces in the U.S. is tied to laundering illicit fentanyl profits.
A Quebec man who pleaded guilty to threatening Prime Minister Justin Trudeau and Premier François Legault has been sentenced to 20 months in jail.
RCMP say human remains found in a rural area in central Saskatchewan may have been there for a decade or more.
A source close to singer Britney Spears tells CNN that the pop star is 'home and safe' after she had a 'major fight' with her boyfriend on Wednesday night at the Chateau Marmont in West Hollywood.
As Wegovy becomes available to Canadians starting Monday, a medical expert is cautioning patients wanting to use the drug to lose weight that no medication is a ''magic bullet,' and the new medication is meant particularly for people who meet certain criteria related to obesity and weight.
Drew Carey took over as host of 'The Price Is Right' and hopes he’s there for life. 'I'm not going anywhere,' he told 'Entertainment Tonight' of the job he took over from longtime host Bob Barker in 2007.
Alberta Ballet's double-bill production of 'Der Wolf' and 'The Rite of Spring' marks not only its final show of the season, but the last production for twin sisters Alexandra and Jennifer Gibson.
A British Columbia mayor has been censured by city council – stripping him of his travel and lobbying budgets and removing him from city committees – for allegedly distributing a book that questions the history of Indigenous residential schools in Canada.
Three men in Quebec from the same family have fathered more than 600 children.
A group of SaskPower workers recently received special recognition at the legislature – for their efforts in repairing one of Saskatchewan's largest power plants after it was knocked offline for months following a serious flood last summer.
A police officer on Montreal's South Shore anonymously donated a kidney that wound up drastically changing the life of a schoolteacher living on dialysis.
Since 1932, Montreal's Henri Henri has been filled to the brim with every possible kind of hat, from newsboy caps to feathered fedoras.
Police in Oak Bay, B.C., had to close a stretch of road Sunday to help an elephant seal named Emerson get safely back into the water.
Out of more than 9,000 entries from over 2,000 breweries in 50 countries, a handful of B.C. brews landed on the podium at the World Beer Cup this week.
Raneem, 10, lives with a neurological condition and liver disease and needs Cholbam, a medication, for a longer and healthier life.