Delta variant will likely become main strain in Ontario, but vaccines can stop spread: officials

Ontario’s associate chief medical officer of health says the Delta COVID-19 variant, first identified in India, will likely become the main strain of the virus in the province, but vaccinations can still stop its spread.

“I think it’s fair to say that Delta strain will become the predominant strain in Ontario, just as has happened in other jurisdictions, particularly the U.K.,” Dr. Barbara Yaffe said Monday.

Yaffe said it may be a similar situation to the Alpha variant, first identified in the United Kingdom, that became dominant in Ontario.

“When these new strains come that are more highly infectious, more transmissible, they do tend to become predominant,” she said.

“I believe we’ve had it now in pretty much every health unit, including some outbreaks in long-term care facilities, where people have been immunized, although they luckily have much less serious infections.”

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Yaffe said those who are vaccinated, particularly those who have received two doses and are fully vaccinated, are well protected against the Delta variant.

“The more people are protected, the less the strain can spread,” she said.

Ontario chief medical officer of health Dr. David Williams said public health information showed the Delta variant had already been circulating “fairly widely” in some areas, such as Peel Region and parts of Toronto, with up to 30 per cent of cases being the Delta strain in mid-May.

Williams said officials thought if public health indicators were to start to worsen as a result of the variant’s spread, “we would have seen it, and we haven’t yet, so that is encouraging.”

He said it seems vaccinations have been able to “temper” a May long weekend case spike as well as the spread of the variant, but caution is still needed. He said hospitalizations and case counts continue to move in positive directions.

Williams said first-dose vaccination rates and an acceleration of second-dose timelines will hopefully result in overall case rates continuing to decline, below 500 and even 400 per day over the next few weeks and eventually into the double digits over the summer.

Ontario reported 525 new COVID-19 cases on Monday, marking the lowest daily case count since Sept. 27, Yaffe said.