Health experts said the old nomenclature was imprecise, played into racist stereotypes and fueled stigmatization, making it harder to contain the most recent outbreaks.
China wants to fine-tune its stringent pandemic restrictions to reduce the disruption to daily life caused by lockdowns. But officials are still taking few chances.
The shots may help older, pregnant and immunocompromised Americans dodge serious illness or death. But the doses are not likely to prevent infections in any group, recent studies suggest.
In a so-called natural experiment, two school districts in Boston maintained masking after mandates had been lifted in others, enabling a unique comparison.
The research looked at patients who qualified for the antiviral through age or health conditions. Those who took it shortly after infection were 26 percent less likely to have symptoms 90 days later.