By Kay Lazar 

Hundreds of workers who care for some of the state’s frailest residents, including those in nursing homes and dialysis centers, are failing to get their annual flu shot, placing patients with weak immune systems at risk of serious illness or death, health specialists said.

A new state report, which tracked vaccination rates during last year’s flu season, found that many clinics, ambulatory care facilities, dialysis centers, nursing and rest homes, and adult day health centers reported worker vaccination rates well below 90 percent, the state and federal goal for health facilities.

Among the lowest vaccination rates in Massachusetts facilities were nursing homes with 72 percent; clinics 68 percent; rest homes 64 percent; and 61 percent at day health programs, which provide community-based nutritional, rehabilitative, and other services to disabled adults.

In response, Massachusetts regulators are now intensifying efforts to improve vaccination rates — sending reminder letters to dozens of facilities that failed to report their numbers, visiting dialysis centers to review their process for vaccinating workers, and even offering cash to nursing homes as an incentive to improve their rates.

“First and foremost, health care personnel are directly interacting with residents and patients. They could be transmitting influenza to them and we want to prevent that from happening,” said Katherine Fillo, director of clinical quality improvement at the Massachusetts Department of Public Health.

High vaccination rates also help ensure that a large number of caregivers don’t fall ill during a flu outbreak, Fillo said.

State regulations require all health care facilities, as a condition of receiving a license, to provide free flu shots each year to all employees. Yet workers are allowed to decline the shot. Facilities must report to the state how many declined and how many cited medical reasons for opting out. They must also report how many workers had an unknown vaccination status.

A recent report from the US Centers for Disease Control and Prevention found that health care workers in the Northeast had the lowest flu vaccination rates in the United States. It also found that rates nationwide were lowest among those who worked in long-term care, such as in nursing homes.

In Massachusetts, among the 315 nursing homes that reported data to the state health department, roughly 16 percent of workers declined to be vaccinated. That’s down slightly from 18 percent in 2017.

Tara Gregorio, president of the Massachusetts Senior Care Association, a trade association, said nursing home administrators are working diligently to increase rates but often encounter barriers.

“Some of our staff decline vaccination for religious or health reasons and others are concerned that the vaccine is ineffective or dangerous,” she said in a statement. “Our efforts to educate everyone in our facilities on the benefits of the flu vaccine are ongoing and a top priority.”

For nursing and rest homes that achieve at least a 90 percent vaccination rate this flu season, the state will reimburse the cost of renewing their license, which can run up to $1,000.

Among the 61 dialysis centers that reported vaccination rates, 83 percent of workers got a flu shot and roughly 9 percent declined. The rest cited medical reasons or their status was unknown.

Dr. Holly Kramer, president of the National Kidney Foundation and a professor of medicine at Loyola University Chicago, said patients receiving dialysis are at particular risk for serious complications from the flu because they often have a greatly weakened immune system.

“The health care workers need to be vaccinated because dialysis patients are more likely to develop severe influenza and need to be hospitalized and can die from influenza,” Kramer said.

Fresenius Medical Care North America, the largest dialysis center chain in Massachusetts with more than 35 centers, said in a statement that it has worked hard to educate patients and employees about the benefits of receiving a flu shot.

Fresenius said that about 86 percent of its workers in Massachusetts were vaccinated last flu season, higher than the industry average here of 83 percent.

“Our policy mandates that any health care provider working with patients in our dialysis centers receive a flu vaccine each season, and if an employee refuses, requires that employee to wear a face mask when near patients,” said Fresenius spokesman Brad Puffer.

“We continue to invest significant resources in reminding both employees and patients about the dangers of flu for people living with kidney failure, and we are committed to further improving these efforts,” he said.

For years, regulators focused on boosting flu vaccinations among hospital workers, which as recently as a decade ago was mired below 70 percent. The state health department started publishing a list of vaccination rates at each facility, and many hospitals started cracking down on workers who declined shots, making them wear masks for the entire flu season. A number of hospitals required caregivers to receive a flu shot each year as a condition of employment.

Rates slowly but steadily climbed, and for the last several years have been above 90 percent.

“Some health care providers use creative ways to ensure vaccination compliance, such as offering vaccinations on-site around the clock and allowing employees to use work time to be inoculated,” said Patricia Noga, vice president for clinical affairs at the Massachusetts Health and Hospital Association.

She said the association strongly supports new policies to improve statewide rates, including requiring the entire health care workforce be vaccinated.

For now, regulators are turning their attention to the rest of the state’s health facilities with a goal of matching the success it had with hospitals.

“We hope and anticipate we will see this same trajectory in these other types of healthcare facilities,” Fillo said.