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
Doctors ask Liberal government to reconsider capital gains tax change
The Canadian Medical Association is asking the federal government to reconsider its proposed changes to capital gains taxation, arguing it will affect doctors' retirement savings.
Keeping these exotic pets is 'cruel' and 'dangerous,' Canadian animal advocates say
Canadian pet owners are finding companionship beyond dogs and cats. Tigers, alligators, scorpions and tarantulas are among some of the exotic pets they are keeping in private homes, which pose risks to public safety and animal welfare, advocates say.
Prince William and wife Kate thank public for birthday messages for son Louis
Prince William and his wife Kate thanked the public for their messages which had been sent to mark the sixth birthday of their youngest son Louis on Tuesday.
She was the closest she'd ever been to meeting her biological father. Then life dealt her a blow
Anne Marie Cavner was the closest she'd ever been to meeting her biological father, but then life dealt her a blow. From an unexpected loss to a host of new relationships, a DNA test changed her life, and she doesn't regret a thing.
How quietly promised law changes in the 2024 federal budget could impact your day-to-day life
The 2024 federal budget released last week includes numerous big spending promises that have garnered headlines. But, tucked into the 416-page document are also series of smaller items, such as promising to amend the law regarding infant formula and to force banks to label government rebates, that you may have missed.
Which foods have the most plastics? You may be surprised
'How much plastic will you have for dinner, sir? And you, ma'am?' While that may seem like a line from a satirical skit on Saturday Night Live, research is showing it's much too close to reality.
'Catch-and-kill' strategy to be a focus as testimony resumes in Trump hush money case
A veteran tabloid publisher was expected to return to the witness stand Tuesday in Donald Trump's historic hush money trial.
Quebec farmers have been protesting since December. Is anyone listening?
Upset about high interest rates, growing paperwork and heavy regulatory burdens, protesting farmers have become a familiar sight across Quebec since December.
South Korean sentenced to 14 months in jail for killing 76 cats
South Korean man has been sentenced to 14 months in prison for killing 76 cats in one of the country's most gruesome cases of animal cruelty in recent years.