RICHMOND — Three former patients from Canterbury Rehabilitation & Healthcare Center outside Richmond have died of coronavirus since Tuesday, and more than a dozen other patients and staff are infected.

But a top local health official said staff at the long-term care facility still lack the protective gear needed to fully contain the spread of what is one of the largest outbreaks of the virus in the greater Washington area.

Over the last 11 days, a total of 14 patients and four staff have tested positive from the rehabilitation facility, which serves mostly senior citizens who are recovering from injuries or illnesses.

Two residents remained hospitalized, and workers at the 190-bed facility are caring for the rest in a wing separate from other patients. An undisclosed number of suspected cases have been separately isolated.

Canterbury workers caring for patients with confirmed and suspected coronavirus cases have the necessary gowns, masks and other equipment to take the highest precautions, said Danny Avula, director of the Henrico County and Richmond Health Departments.

But the same is not true for those working with Canterbury patients who appear healthy, Avula said.

The situation could lead to the further spread of the virus, he said, given the hands-on nature of the work and the virus’s ability to spread from person to person before patients show symptoms.

“In settings like this, health care workers may need to use PPE [personal protective equipment] for every patient whether they have symptoms or not, but it’s just not possible given the limited PPE supplies the entire nation is facing,” he said.

Canterbury announced Tuesday that two of its patients had died at a regional hospital. One was a man in his 60s, the other a woman in her 80s, both with underlying conditions, Avula said.

The third fatality, of a man in his 70s, was announced Wednesday.

About a week before Canterbury confirmed its first case, the facility’s medical director and other directors of similar facilities begged state health officials to change their testing criteria so more people could be tested for the virus.

At the time, with tests in short supply nationally, the state required that patients in long-term care facilities be screened for flu and undergo a respiratory virus panel before being tested for coronavirus.

Those requirements delayed testing for the most vulnerable population as long as a week, according to the March 18 letter, which blasted the state health department for authorizing a community screening that week in Henrico County for younger, healthier people.

“At a time when our long-term care facilities have limited access even to the necessary screening equipment to perform the prerequisite testing, we feel very strongly that screening centers for younger patients represent a misappropriation of limited resources, putting our elders at unnecessary risk,” the letter said.

The state loosened its testing criteria for long-term care facilities a few days later, dropping the requirement that other respiratory viruses be ruled out first. The flu test requirement remains.

Canterbury is working with state and local health departments while following Centers for Disease Control and Prevention protocols to “help contain further spread of the virus,” Jim Wright, the facility’s medical director, said in a statement announcing the deaths.

The facility has hired an industrial cleaning service to perform “daily deep cleaning” and installed six machines known as hydroxyl generators, which treat pathogens in the air and on surfaces.

Canterbury is monitoring residents for symptoms and preventing employees with respiratory symptoms and fever from entering. The facility said it suspended new admissions and visitors before its first confirmed case.

While it announces new cases throughout the state daily, Virginia has not routinely disclosed the number of infections at health-care facilities or nursing homes. The state previously reported that a resident at Westminster Canterbury, an unaffiliated senior facility in Richmond, had tested positive for the virus. Avula said that person remains hospitalized.

Canterbury Rehab notified the local health department immediately after identifying its first case last Wednesday, said Avula. He praised the facility for quickly creating a separate wing to isolate patients who had tested positive and notifying families of all residents about the diagnoses.

“We were on the phone with them until close to midnight,” he said. “They did so many of the right things immediately. ... I can’t say enough about their efforts from an infection-control standpoint.”

County and state officials have continued to work closely with the facility, including multiple visits by nurses and epidemiologists, Avula said. But he added that the nature of coronavirus, and the shortage of protective equipment, has made it tough to stop the spread of infection.

“My people came back and said, ‘I really think they’re doing everything they can,’” Avula said.