More Than 80 Percent of Seniors Are Vaccinated. That’s ‘Not Safe Enough.’

Nearly 10 million older people are without full immunization. That not only endangers them, but provides opportunities for the coronavirus to keep mutating in the bodies of those with weak immune systems. It could also complicate the planned distribution of third shots.

Last winter, when the vaccines became available, the older cohort got a head start.

“They were the first in line,” said David Grabowski, a health care policy researcher at Harvard Medical School. Seniors were among those who received priority for appointments, while a federal program brought vaccine clinics directly to nursing homes. And many were inclined to roll up their sleeves.

“A lot of older adults realized they were at risk,” said Dr. David Nace, a geriatrician at the University of Pittsburgh Medical Center who researches infections in older adults. “We have an older population that recalls what it was like before the polio vaccine or the diphtheria vaccine.”

Statistics from the Centers for Disease Control and Prevention showed this population’s vaccination rates soaring through the spring, then hitting a plateau. Among 65- to 74-year-olds, 80 percent were fully vaccinated on July 1, creeping gradually to almost 84 percent by Sept. 1. Among those over 75, about 76 percent were fully vaccinated on July 1 and about 79 percent now.

Those numbers conceal enormous regional variations. Dane County, Wisconsin, which includes Madison, has reached almost universal vaccination for those over 65. But only 75 percent are fully vaccinated in Los Angeles County.

In New York City, rates for those over age 65 range from 80 percent on Staten Island to just 67 percent in Brooklyn. The rate falls below 50 percent in several Alabama counties and below 40 percent in stretches of New Mexico.

Even older people who want the shots can face substantial obstacles. Early on, with local health authorities operating mass vaccination sites, “some older adults couldn’t manage the online registration, or couldn’t get to a center,” Dr. Grabowski said.