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
'A beautiful soul': Funeral held for baby boy killed in wrong-way crash on Highway 401
A funeral was held on Wednesday for a three-month-old boy who died after being involved in a wrong-way crash on Highway 401 in Whitby last week.
'Sophisticated' cyberattacks detected on B.C. government networks, premier says
There has been a "sophisticated" cybersecurity breach detected on B.C. government networks, Premier David Eby confirmed Wednesday evening.
Police handcuff man trying to enter Drake's Toronto mansion
Toronto police say a man was taken into custody outside Drake's Bridle Path mansion Wednesday afternoon after he tried to gain access to the residence.
Biden says he will stop sending bombs and artillery shells to Israel if they launch major invasion of Rafah
U.S. President Joe Biden said for the first time Wednesday he would halt shipments of American weapons to Israel, which he acknowledged have been used to kill civilians in Gaza, if Prime Minister Benjamin Netanyahu orders a major invasion of the city of Rafah.
Canucks beat Oilers 5-4 in comeback to take Game 1
The Vancouver Canucks won the first game of their NHL playoffs series with the Edmonton Oilers 5-4 on Wednesday night coming back from a three-goal deficit.
Nijjar murder suspect says he had Canadian study permit in immigration firm's video
One of the Indian nationals accused of murdering British Columbia Sikh activist Hardeep Singh Nijjar says in a social media video that he received a Canadian study permit with the help of an Indian immigration consultancy.
Pfizer agrees to settle more than 10K lawsuits over Zantac cancer risk: Bloomberg News
Pfizer has agreed to settle more than 10,000 lawsuits about cancer risks related to the now discontinued heartburn drug Zantac, Bloomberg News reported on Wednesday, citing people familiar with the deal.
Quebec premier defends new museum on Quebecois nation after Indigenous criticism
Quebec Premier Francois Legault is defending his comments about a new history museum after he was accused by a prominent First Nations group of trying to erase their history.
U.S. presidential candidate RFK Jr. had a brain worm, has recovered, campaign says
Independent U.S. presidential candidate Robert F. Kennedy Jr. had a parasite in his brain more than a decade ago, but has fully recovered, his campaign said, after the New York Times reported about the ailment.