Delta variant rising 'rapidly' in Ontario but vaccines offer better protection than previously thought: Yaffe
The highly infectious Delta variant is on track to become the dominant strain of COVID-19 in Ontario, but there is hope that vaccines offer more protection against it than previously thought, one of Ontario's top doctors says.
“Yes it's true that the Delta variant is growing rapidly in Ontario,” Associate Chief Medical Officer of Health Dr. Barbara Yaffe said during a news conference Monday.
While the Alpha variant first identified in the U.K. has dominated Ontario for months, the Delta variant, first identified in India, has accounted for a rapidly growing share of the province’s new COVID-19 infections.
“Rapidly, the U.K. one is going down and the Delta is going up so we fully expect it will become the predominant strain,” Yaffe said.
She pointed out the Delta variant is around one and a half times more transmissible than the Alpha variant.
While a study suggesting that a single vaccine dose offers around 33 per cent protection against the Delta variant has been widely cited by local health officials, Yaffe said Monday that new research suggests that a single vaccine dose is more effective than first thought.
“But in real life, it appears that, certainly with the mRNA vaccines, that it's more like 47 to 48 per cent effective,” Yaffe said.
She pointed out that that figure speaks to how many people with a single vaccine dose developed any symptom of COVID-19 at all.
“In terms of severe infection, even one dose is quite protective,” Yaffe added.
New research into the Delta variant released by Public Health England this week suggests that after a single dose, Pfizer was 94 per cent effective against hospitalization, while AstraZeneca was 71 per cent effective.
Yaffe said two doses of an mRNA vaccine appear to be around 88-90 per cent effective at preventing symptomatic COVID-19, while two doses of AstraZeneca appear to be around 60-70 per cent effective at preventing any COVID-19 symptoms at all.
“That's one of the reasons we're pushing up the interval between the first dose of AstraZeneca, and the second dose of whichever vaccine the individual chooses, because we want to get people as fully protected as possible as quickly as possible with the Delta strain moving up in Ontario as it is,” Yaffe said.
While Ontario had originally spaced out vaccine doses at 16 weeks to try and extend a basic level of protection to as many people as possible more quickly, the province has begun accelerating second doses as a steady and plentiful supply of vaccines arrives.
The province is also allowing anyone who received a first dose of AstraZeneca to get a second dose of an mRNA vaccine and over the weekend said that people who received AstraZeneca for the first dose would have to wait just eight weeks instead of 12 to receive a second dose.
CTVNews.ca Top Stories
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.
‘We made them safer and more fun’: Here’s what’s new about e-scooters
Electric scooters (e-scooters) have been gaining popularity in the capital and this season comes with some changes and updates.
The kids from 'Mrs. Doubtfire' are all SUPER grown up now, and we're not OK
The adorable trio of child actors from the 1993 classic comedy 'Mrs. Doubtfire,' which starred the late and great Robin Williams, are all grown up and looking back on their seminal time together.
Premier Legault reiterates that McGill pro-Palestinian camp must be dismantled
Quebec Premier François Legault reiterated that the pro-Palestinian encampment at McGill University must be dismantled while police remain 'on the lookout for new developments.'
Houston braces for flooding to worsen in wake of storms
High waters flooded neighborhoods around Houston on Saturday following heavy rains that have already resulted in crews rescuing hundreds of people from homes, rooftops and roads engulfed in murky water.
Canadian Auger-Aliassime reaches first Masters final in Madrid with another walkover
Montreal's Felix Auger-Aliassime has advanced to his first ATP Masters final, and he hasn't had to play all that much tennis to do it.
Drew Carey is never quitting 'The Price Is Right'
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.
The UN warns Sudan's warring parties that Darfur risks starvation and death if aid isn't allowed in
The United Nations food agency warned Sudan's warring parties Friday that there is a serious risk of widespread starvation and death in Darfur and elsewhere in Sudan if they don't allow humanitarian aid into the vast western region.
Two killed after collision with truck on Hwy. 417 near Limoges, Ont.
Ontario Provincial Police say two people were killed after a car and a transport truck collided in the westbound lanes of Highway 417 near Limoges, Ont. on Tuesday afternoon.