Older adults are currently the most vaccinated age group in the U.S., though about a fifth of those 65 and older haven't received even one shot, reports the CDC.
Some scientists and health officials worry that some Americans most vulnerable to COVID-19, such as those 65 and older, may have more difficulty getting a shot now that all adults are eligible, reports The New York Times.
The eligibility expansion may spur the opening of more mass vaccination sites, but the sites could be intimidating or uncomfortable for anyone who is particularly vulnerable to the virus, said Cindy Prins, PhD, an epidemiologist at Gainesville-based University of Florida.
"I think there are some folks who want to get the vaccine, but they're still very worried about getting exposed to other people," Dr. Prins told the Times. "It's a little bit of a strange situation where we're like, 'Stay away from everyone, but please come here to our massive vaccine clinic.'"
Other reasons eligible people may not get vaccinated include supply issues, limited access to vaccination sites, or vaccine hesitancy or refusal.
As of April 20, almost 40 percent of the U.S. population has received at least one COVID-19 shot.