Â鶹ӰÊÓ

Skip to main content

COVID-19 herd immunity unlikely, but 'herd resistance' a possibility, experts say

Share

Is Omicron leading us closer to herd immunity against COVID-19?

Experts say it's not likely that the highly transmissible variant -- or any other variant -- will lead to herd immunity.

"Herd immunity is an elusive concept and doesn't apply to coronavirus," says Dr. Don Milton at the University of Maryland School of Public Health.

Herd immunity is when enough of a population is immune to a virus that it's hard for the germ to spread to those who aren't protected by vaccination or a prior infection.

For example, herd immunity against measles requires about 95 per cent of a community to be immune. Early hopes of herd immunity against the coronavirus faded for several reasons.

One is that antibodies developed from available vaccines or previous infection dwindle with time. While vaccines offer strong protection against severe illness, waning antibodies mean it's still possible to get infected -- even for those who are boosted.

Then there's the huge variation in vaccinations. In some low-income countries, less than 5 per cent of the population is vaccinated. Rich countries are struggling with vaccine hesitancy. And young children still aren't eligible in many places.

As long as the virus spreads, it mutates -- helping the virus survive and giving rise to new variants. Those mutants -- such as Omicron -- can become better at evading the protection people have from vaccines or an earlier infection.

Populations are moving toward "herd resistance," where infections will continue, but people have enough protection that future spikes won't be as disruptive to society, Milton says.

Many scientists believe COVID-19 will eventually become like the flu and cause seasonal outbreaks but not huge surges.

CTVNews.ca Top Stories

The British Columbia election campaign is set to officially start today, with Lt.-Gov. Janet Austin issuing the writ for the Oct. 19 vote.

A northern Ontario man is facing a $12,000 fine after illegally shooting a moose near the Batchawan River.

Unusual flippered feet are making their way into the Saint Lawrence River this weekend. Led by underwater explorer and filmmaker Nathalie Lasselin, volunteer divers are combing the riverbed near Beauharnois in Montérégie to remove hundreds of tires that have been polluting the aquatic environment for decades.

A sea lion swam free after a rescue team disentangled it near Vancouver Island earlier this week.

Local Spotlight

Cole Haas is more than just an avid fan of the F.W. Johnson Wildcats football team. He's a fixture on the sidelines, a source of encouragement, and a beloved member of the team.

Getting a photograph of a rainbow? Common. Getting a photo of a lightning strike? Rare. Getting a photo of both at the same time? Extremely rare, but it happened to a Manitoba photographer this week.

An anonymous business owner paid off the mortgage for a New Brunswick not-for-profit.

They say a dog is a man’s best friend. In the case of Darren Cropper, from Bonfield, Ont., his three-year-old Siberian husky and golden retriever mix named Bear literally saved his life.

A growing group of brides and wedding photographers from across the province say they have been taken for tens of thousands of dollars by a Barrie, Ont. wedding photographer.

Paleontologists from the Royal B.C. Museum have uncovered "a trove of extraordinary fossils" high in the mountains of northern B.C., the museum announced Thursday.

The search for a missing ancient 28-year-old chocolate donkey ended with a tragic discovery Wednesday.

The Royal Canadian Mounted Police is celebrating an important milestone in the organization's history: 50 years since the first women joined the force.

It's been a whirlwind of joyful events for a northern Ontario couple who just welcomed a baby into their family and won the $70 million Lotto Max jackpot last month.

Stay Connected