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
Grandparent scam: London, Ont., senior beats fraudsters not once, but twice
It was a typical Tuesday for Mabel Beharrell, 84, until she got the call that would turn her world upside down. Her teenaged grandson was in trouble and needed her help.
Deaths of 4 people on Sask. farm confirmed as murder-suicide
The deaths of four people on a farm near the Saskatchewan village of Neudorf have been confirmed a murder-suicide.
CRA no longer requiring 'bare trust' reporting in 2023 tax return
The Canada Revenue Agency announced Thursday it will not require 'bare trust' reporting from Canadians that it introduced for the 2024 tax season, just four days before the April 2 deadline.
Full parole granted to man convicted in notorious 'McDonald's murders' in Cape Breton
The Parole Board of Canada has granted full parole to one of three men convicted in the brutal murders of three McDonald's restaurant workers in Cape Breton more than 30 years ago.
Incident on Calgary's Reconciliation Bridge comes to safe resolution
Nearly 20 hours after a man climbed and remained perched on top of the Reconciliation Bridge in downtown Calgary, the situation came to a peaceful resolution.
Sunshine list: These were the Ontario public sector's highest earners in 2023
Ontario released its annual sunshine list Thursday afternoon, noting that the largest year-over-year increases were in hospitals, municipalities, and post-secondary sectors.
George Washington family secrets revealed by DNA from unmarked 19th century graves
Genetic analysis has shed light on a long-standing mystery surrounding the fates of U.S. President George Washington's younger brother Samuel and his kin.
'We won't forget': How some Muslims view Poilievre's stance on Israel-Hamas war
A spokesman for a regional Muslim advocacy group says Conservative Leader Pierre Poilievre's stance on the Israel-Hamas war could complicate his party's relationship with Muslim Canadians.
Why some Christians are angry about Trump's 'God Bless the USA' Bible
Former U.S. President Donald Trump is officially selling a copy of the Bible themed to Lee Greenwood’s famous song, 'God Bless the USA.' But the concept of a Bible covered in the American flag has raised concern among religious circles.