This winter's omicron wave in the U.S. also bolstered our defenses, leaving enough protection against the coronavirus that future spikes will likely require much less disruption to society.
Millions of individual Americans’ immune systems now recognize the virus and are primed to fight it off if they encounter omicron, or even another variant.
One influential model looks at vaccinations, recent infections and other factors to estimate that 73% of Americans are, for now, immune to omicron, and that could rise to 80% by mid-March.
Still, while the population is better protected, tens of millions of individuals are not because they are unvaccinated or have never been infected.
