As COVID-19 cases in the U.S. drop, the hospitalization rate remains high — as does the death rate. Experts say getting a COVID vaccine booster is key to maintaining immunity, but only about half of all vaccinated people in the U.S. have gotten the booster, which increases protection against both serious illness and death from the Omicron variant. Still, many infectious disease experts are cautiously optimistic for the coming months, pointing to it as a time to bolster our defenses against the virus. Reach the show by emailing shortwave@npr.org.