Second doses needed to contain Delta variant even as Ontario makes "excellent progress"

Jun 10 2021, 1:41 pm

Although Ontario’s latest COVID-19 modelling suggests a promising summer trajectory now that new infections, hospitalization rates, and test positivity are all coming down, officials say containing the Delta variant is critical.

A continued focus on getting second doses to hard-hit areas and older adults is needed to bring new Delta variant cases under control, health officials said during a modelling update Thursday.

“This is not a doomsday scenario, and we can control the Delta variant with the right actions,” said Dr. Steini Brown, co-chair of the COVID-19 Science Advisory table.

The Delta variant fuelled a deadly COVID-19 resurgence in India this year. It’s estimated to be 50% more transmissible than the Alpha variant originally discovered in the UK, which was 50% more transmissible than the original strain of COVID-19.

The Delta variant is already here in Ontario, and health officials estimate it will become the dominant strain over the summer. When someone becomes infected with the Delta variant, their risk of being admitted to a hospital is higher.

A first dose of the COVID-19 vaccine provides weakened protection against the Delta variant compared to the original strain. Six in 10 people are protected from symptomatic infection with the original COVID-19 strain after one dose, but that drops to about four in 10 people for the Delta variant.

The good news is that a second dose boosts protection against the Delta variant.

Delta variant

Government of Ontario

The Ontario government announced it would prioritize Delta variant hotspot regions for second doses this month. Starting June 14, everyone living in Toronto, Peel, York, Halton, Waterloo, Wellington-Dufferin-Guelph and Porcupine will be eligible to book their second shot.

At the beginning of the year, hotspot neighbourhoods with high rates of COVID-19 infection had the worst vaccine coverage. Now, with a focus on allocating more doses to the hardest-hit areas, Ontario has reversed that trend. First dose vaccine coverage for adults is now similar in low-risk and high-risk neighbourhoods.

Delta variant

COVID-19 Science Table

The only exception is the oldest band of adults, where seniors in high-risk neighbourhoods are less likely to be vaccinated. Brown suggested community-specific tailored approaches such as incorporating primary care providers and using mobile clinics as a way to reach those seniors.

The modelling forecast for the summer now looks encouraging, and experts believe new infections will continue falling as more people become fully immunized. Brown said Ontario is likely to follow a trajectory somewhere between the green (best-case scenario) and yellow lines in the latest modelling.


COVID-19 Science Table

Hospitalization continues to fall, although they’re still higher than they were at the peak of the second wave. ICU admissions are a lagging indicator, and Brown does expect that figure to come down over the summer.

Delta variant

COVID-19 Science Table

Ontario is entering Stage 1 of its reopening plan on Friday, when restaurant patios, retail stores, and outdoor pools will be allowed to reopen. Brown said this round of summer reopening is more encouraging because more people are vaccinated than last year.

“Thank you,” Brown said. “This is the hard work of Ontarians and making sure people get vaccinated.”

Megan DevlinMegan Devlin

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