Omicron dims hope for achieving herd immunity against COVID-19, experts say

Hopes for herd immunity dimmed as the virus mutated into new variants in quick succession, enabling it to reinfect people who were vaccinated or had previously contracted COVID-19.

The Omicron variant, which is spreading far faster than previous versions of the coronavirus, is not likely to help countries achieve so-called herd immunity against COVID-19, in which enough people become immune to the virus that it can no longer spread, leading disease experts say.

From the earliest days of the pandemic, public health officials have expressed hope that it was possible to achieve herd immunity against COVID-19, as long as a high enough percentage of the population was vaccinated or infected with the virus.

Those hopes dimmed as the coronavirus mutated into new variants in quick succession over the past year, enabling it to reinfect people who were vaccinated or had previously contracted COVID-19.

Some health officials have revived the possibility of herd immunity since Omicron emerged late last year.

The fact that the variant spreads so quickly and causes milder illness might soon expose enough people, in a less harmful way, to the SARS-COV-2 virus and provide that protection, they argue.

Disease experts note, however, that Omicron’s transmissibility is aided by the fact that this variant is evenbetter than its predecessors at infecting people who were vaccinated or had a prior infection. That adds to evidence that the coronavirus will continue to find ways to break through our immune defenses, they said.

“Reaching a theoretical threshold beyond which transmission will cease is probably unrealistic given the experience we have had in the pandemic,” Dr. Olivier le Polain, an epidemiologist with the World Health Organization (WHO), told Reuters.