Indian envoy warns of 'big red line,' days after charges laid in Nijjar case
India's envoy to Canada insists relations between the two countries are positive overall, despite what he describes as 'a lot of noise.'
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.
India's envoy to Canada insists relations between the two countries are positive overall, despite what he describes as 'a lot of noise.'
With Donald Trump sitting just feet away, Stormy Daniels testified Tuesday at the former president's hush money trial about a sexual encounter the porn actor says they had in 2006 that resulted in her being paid to keep silent during the presidential race 10 years later.
The U.S. paused a shipment of bombs to Israel last week over concerns that Israel was approaching a decision on launching a full-scale assault on the southern Gaza city of Rafah against the wishes of the U.S.
Footage from dozens of security cameras in the area of Drake’s Bridle Path mansion could be the key to identifying the suspect responsible for shooting and seriously injuring a security guard outside the rapper’s sprawling home early Tuesday morning, a former Toronto homicide detective says.
A chicken farmer near Mattawa made an 'eggstraordinary' find Friday morning when she discovered one of her hens laid an egg close to three times the size of an average large chicken egg.
Susan Buckner, best known for playing peppy Rydell High School cheerleader Patty Simcox in the 1978 classic movie musical 'Grease,' has died. She was 72.
Accused killer Jeremy Skibicki could have a challenging time convincing a judge that he is not criminally responsible for the deaths of four Indigenous women, a legal analyst says.
A Calgary bylaw requiring businesses to charge a minimum bag fee and only provide single-use items when requested has officially been tossed.
Two Nova Scotia men are dead after a boat they were travelling in sank in the Annapolis River in Granville Centre, N.S., on Monday.
An Ontario man says he paid more than $7,700 for a luxury villa he found on a popular travel website -- but the listing was fake.
Whether passionate about Poirot or hungry for Holmes, Winnipeg mystery obsessives have had a local haunt for over 30 years in which to search out their latest page-turners.
Eighty-two-year-old Susan Neufeldt and 90-year-old Ulrich Richter are no spring chickens, but their love blossomed over the weekend with their wedding at Pine View Manor just outside of Rosthern.
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 mother goose and her goslings caused a bit of a traffic jam on a busy stretch of the Trans-Canada Highway near Vancouver Saturday.
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.