Delta COVID-19 variant has pushed vaccine target further: Tam

There's no definitive word on just how many people need to be vaccinated against COVID-19 to reach herd immunity.

There’s no definitive word on just how many people need to be vaccinated against COVID-19 to reach herd immunity but, whatever it is, Canada’s top doctor says the highly contagious Delta variant has set the goalpost even farther away.

Dr. Theresa Tam, Canada’s chief public health officer, has previously said she would like to see all eligible age groups at least 80 per cent fully vaccinated as soon as possible to fight the surge in COVID-19 cases.

As of the latest update, that’s true for everyone over the age of 50, with people in their 40s close behind at 79 per cent.

“Delta variant, of course, being more transmissible has led to an increase in vaccine coverage level requirement to help move towards community immunity, or herd immunity,” Tam said at a briefing Friday.

Herd immunity — when enough people have been vaccinated that COVID-19 can no longer thrive — has been described as the finish line for the pandemic: if only enough people get vaccinated, Canada could cross that line and life could return more or less to normal.

Tam suggested vaccination coverage may now need to be 80 per cent for the whole population, as opposed to just those who qualify for the vaccine.

While 81 per cent of those who qualify are fully vaccinated, Canada’s total population is only about 70 per cent vaccinated. There’s no vaccine currently approved for children under 12.

Public Health Ontario went even farther in a July evidence brief related to the province’s reopening plans.