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% 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% 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.
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