Why we will not see herd immunity for COVID-19
Why we will not see herd immunity for COVID-19

Why we will not see herd immunity for COVID-19

Does omicron bring us closer to herd immunity to COVID-19?

Experts say it is unlikely that the highly transmissible variant – or any other variant – will lead to herd immunity.

“Flock immunity is an elusive concept and does not apply to coronavirus,” says Dr. Don Milton at the University of Maryland School of Public Health.

Flock immunity is when enough of a population is immune to a virus that it is difficult for the germ to spread to those who are not protected by vaccination or a previous infection.

For example, herd immunity to measles requires that about 95% of a community be immune. Early hopes of herd immunity to coronavirus faded for several reasons.

One is that antibodies developed from available vaccines or previous infection shrink over time. While vaccines provide strong protection against serious illness, declining antibodies mean that it is still possible to become infected – even for those who are boosted.

Then there is the great variety in vaccinations. In some low-income countries, less than 5% of the population is vaccinated. Rich countries are struggling with the vaccination dust. And young children are still not eligible in many places.

As long as the virus spreads, it mutates – helping the virus survive and giving rise to new variants. These mutants – such as omicron – may be better able to avoid the protection people have against vaccines or a previous infection.

Populations are moving toward “herd resistance,” where infections will continue, but people have adequate protection so that future increases will not be so disruptive to society, Milton says.

Many researchers believe that COVID-19 will eventually become like the flu and cause seasonal outbreaks, but not large increases.

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