愛污传媒

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

Angela Salvatore had been away from her father's hospital bedside for just over an hour when she says she got a frantic call from a nurse, pleading with her to calm him down.

Canadian Ryan James Wedding finished in 24th place in the parallel giant slalom at the 2002 Winter Games in Salt Lake City, but the snowboarder wouldn鈥檛 go on to improve his results in Torino four years later.

The mystery of a 100-year-old letter sent from Manitoba to Ireland is slowly unraveling thanks to the work of one amateur sleuth.

Local Spotlight

A new resident at a Manitoba animal rescue has waddled her way into people's hearts.

Hundreds of people ran to the music of German composer and pianist Beethoven Wednesday night in a unique race in Halifax.

He is a familiar face to residents of a neighbourhood just west of Roncesvalles Avenue.

A meteor lit up our region's sky last night 鈥 with a large fireball shooting across the horizon over Lake Erie at around 7:00 p.m.

Residents of Ottawa's Rideauview neighbourhood say an aggressive wild turkey has become a problem.

A man who lost his life while trying to rescue people from floodwaters, and a 13-year-old boy who saved his family from a dog attack, are among the Nova Scotians who received a medal for bravery Tuesday.

A newly minted Winnipegger is hoping a world record attempt will help bring awareness for the need for more pump track facilities in the city.

A Springfield, Ont. man is being hailed a 'hero' after running into his burning home to save his two infant children.

Hortense Anglin was the oldest graduate to make her way across the platform at York University's Fall Convocation ceremony this week. At the age of 87, she graduated with an Honours degree in Religious Studies.

Stay Connected