COVID-19 herd immunity not a 'magic number' that will end pandemic, Saskatoon virologist says

VIDO-InterVac research scientist and virologist Angela Rasmussen says there remain people who should get their boosters and vaccines in Saskatchewan, which would help achieve herd immunity faster.

“I think people really also need to understand about the herd immunity threshold is it is not some sort of magic number that we hit and all of a sudden the pandemic is over,” she said.

“We really do need to hit the global herd immunity threshold before we will stop seeing new variants emerge.”

The province's Chief Medical Officer Saqib Shahab said this week that the Omicron variant is approaching its peak in Saskatchewan. Shortly after, a rise in hospital pressures will follow, he said.

Rasmussen said the same trends have occurred in Ontario and some states in the United States, with the peak happening over a couple of weeks.

“We are seeing in many places, particularly places that have large unvaccinated populations, that the hospitalizations are not quite as quick to go down as the overall number of cases, so we still might be in for a rough few weeks ahead of us.”

Rasmussen says more than three billion people worldwide haven’t received a single dose of any vaccine yet, and the goal should be to make the human population as inhospitable to viral infection as possible.

“That's why it really is important to hit that global herd immunity threshold rather than national ones because anytime you have a concentration of people, a population of people who are more susceptible, you risk amplifying a variant that might emerge and then that can spread outwards to other places,” she said.