As the seventh wave of COVID-19 develops in parts of the country, many Canadians are now being offered a fourth dose of the vaccine.
In Ontario, starting Thursday, anyone 18 years of age or older who had their first booster shot at least five months ago can now order another.
Other provinces and territories, such as Quebec, Prince Edward Island, Nunavut and Yukon, have also extended eligibility for a second booster – which will be the fourth dose of the vaccine – to anyone on 18 and 12 years old, respectively, have waited a certain number of months since their last dose.
Confused about mixed messages for the 4th dose of COVID? You’re not alone
With questions and mixed messages around the timing of booster shots, many are wondering if they should get the vaccine now or wait until the fall when Pfizer and Moderna are expected to roll out the vaccine. updated divalent is designed to protect against both the parent strain and the Omicron variant of the virus.
Because we’re so vulnerable to the current wave, there’s no reason to delay, says Tania Watts, an immunologist and professor at the University of Toronto.
“Give that fourth dose, it’s going to raise the antibodies again and then they’ll go down,” she said.
“Protection against severe disease in healthy people remains more stable, but there is a transient increase in protection against infection if you get that fourth dose.”
Ontario expands 4th dose of COVID vaccine amid 7th wave
The booster shots currently being offered are formulated to be identical to the first three, based on the original Wuhan strain of COVID-19.
Alberto Martin, professor of immunology at the University of Toronto, said that although the virus has mutated with a new sub-variant of Omicron, BA.5, dominating the spread of COVID-19, the fourth dose of the vaccine is still better not to get vaccinated, says Alberto Martin, a professor of immunology at the University of Toronto.
Is a 4th dose of COVID-19 needed amid Omicron spread? Experts consider
“There’s no doubt the antibody level will go up, but most of it will be against the original variant,” he said.
“It can provide at least a passive protection against reinfection,” Martin told Global News.
Watts said the new variants change the viral sequence where the antibodies bind to the mutant protein. So there’s always some loss of some neutralizing antibodies, she explains, but “it’s not a complete loss.”
“The extra boost can boost your protection again, and there are also other antibodies that don’t necessarily completely stop the infection, but can latch onto the virus somewhere else and help clear it up. book it.”
What British Columbians need to know about the 4th dose of the COVID vaccine
COVID-19 infection has a strengthening effect on the immune system, Watts said, so a fourth dose may not be so urgent at this time for people who already have the virus.
Being infected with COVID-19 adds to the “complexity of the matter” when considering vaccination, according to Dr. Howard Njoo, Canada’s deputy director of public health.
Patient died in NB emergency room, witnesses spoke up
‘A big shock’: Canadians feel squeezed by Central Bank of Canada rate hike
What causes long COVID? Canadian researchers think they have found a key clue
However, because of the risk of long-term consequences of COVID-19, or long-lasting COVID, Njoo said it is better to depend on vaccines for immunity than superinfection.
“What the science is showing us is certainly with vaccination, it’s a more controlled way to get your immunity,” he said at a press conference on Thursday. natural infection.
Watts also said vaccine-induced immunity is “slightly better” than virus-induced immunity in the long run.
“But the combination of vaccine and infection or infection and vaccine seems like another push,” she said.
What does the study show?
There is limited but promising data on the effectiveness of a fourth dose of COVID-19, especially for vulnerable populations.
A new Canadian study published in the British Medical Journal in June found that a fourth dose of the COVID-19 vaccine was associated with strong protection against serious outcomes in people receiving care. long-term care, although the duration of protection is unknown.
4th dose of COVID-19 vaccine: What is the science behind another booster?
The researchers looked at long-term care facilities in Ontario during Omicron-driven waves from December 30, 2021 to April 27, 2022.
Their findings showed that compared with the third dose of the COVID-19 mRNA vaccine, the fourth dose improved protection against infection, symptomatic infection and serious outcomes.
Omicron Auxiliary Fuel Fears of COVID-19 Reinfection
Meanwhile, according to a study published in the New England Journal of Medicine in May, the fourth dose of the COVID-19 vaccine given to people over 60 in Israel made them more resistant to Omicron infections. twice as high as those who received three injections in the same age group. .
Based on existing research, WHO says there is a short-term benefit to adding booster doses to the highest-risk groups, including healthcare workers, people over 60 years of age or with immunocompromised conditions. Translate.
However, according to the World Health Organization, data to support an additional dose in healthy young populations are limited.
“Preliminary data suggest that in young people the benefit is minimal,” it said in a May 2022 statement.
Will you need another vaccine in the fall?
Pfizer and Moderna are currently developing an updated version of their COVID-19 vaccine to better target the Omicron variant and its subtypes.
Both companies expect their two-variant vaccines to be ready for approval in the fall.
COVID-19: How dual-value vaccines can help protect against new variants
Moderna applied to Health Canada for a dual-validation COVID-19 vaccine last month.
According to Moderna Canada, if approved quickly, the doses could be ready for Canadians as early as September.
NACI recommends COVID-19 intensification in the fall before potential wave
So if people get their fourth dose now, they still have the option to get a boost again — but after five to six months for a sufficient immune response, Watts said.
“I don’t think it’s a bad idea if you feel like you can’t avoid exposure easily,” she says.
“And I don’t think it’s going to stop you from getting a booster shot in the fall as we head into respiratory season,” she added.
Martin agreed, saying there was no risk in using further boosters.
“There’s no harm in getting the (fourth) dose of the vaccine now and then potentially getting another Omicron-specific vaccine in the fall,” he said.
– With files from Global News ‘Teresa Wright
© 2022 Global News, a division of Corus Entertainment Inc.
Janaseva News Medium Account