A flurry of coronavirus cases at the District’s public psychiatric hospital and in its homeless shelters has led to quarantine measures this week and calls to improve protections for those who work with some of the city’s most vulnerable residents.

Five employees and one patient have tested positive for the coronavirus at St. Elizabeths Hospital, a public psychiatric facility owned by the District. Twenty-two other employees are in self-quarantine, said D.C. Department of Behavioral Health spokeswoman Erica W. Cunningham.

The affected staff members work in Unit 1D, where some criminal defendants facing trial are housed for psychiatric treatment as courts determine whether they can understand legal proceedings.

District officials said crews sanitized the unit and quarantined the patients living there. The ­165-year-old hospital also created an isolation unit for patients who test positive for the coronavirus or have symptoms.

St. Elizabeths has begun checking the temperatures of everyone seeking to enter the hospital and is preventing patients in different units from mingling, among other measures.

D.C. Mayor Muriel E. Bowser (D) didn’t comment on the St. Elizabeths cases when asked about them at a Wednesday news conference. “I can’t speak to you with any detail,” she said.

Edward J. Smith, executive director of the D.C. Nurses Association, whose membership includes nurses at St. Elizabeths, said the hospital is “not really equipped to handle patients with this type of virus.”

He said he worried the hospital might not have enough equipment such as N95 masks. Smith also said the city’s coronavirus protocols, which do not recommend testing for those not showing symptoms, are not adequate for a facility such as St. Elizabeths, which has about 700 staff members and 270 patients on its campus in Southeast Washington.

“No place as far as I know is testing nurses exposed but not having any symptoms,” he said. “That needs to change. It needs to change fast.”

Andrea Procaccino, a staff attorney at Disability Rights DC, which advocates for patients at St. Elizabeths, said the agency has received several calls from patients with concerns about the health scare.

“St. Elizabeths does not have as robust of an infectious disease department as medical hospitals do,” she wrote in an email. “We are concerned that the infectious disease staff is not prepared for an outbreak and will not have adequate resources and personnel.”

As city officials responded to cases at St. Elizabeths, coronavirus cases also were reported among residents of the city’s shelter system. Bowser said five homeless people have tested positive and 49 people are in quarantine because of their exposure to them.

The positive cases, first reported by Washington City Paper, were found at the Harriet Tubman Women's Shelter in Southeast Washington, Patricia Handy Place for Women in Northwest Washington and the Community for Creative Non-Violence, the city’s largest shelter, near Judiciary Square.

Schroeder Stribling, a member of the city’s Interagency Council on Homelessness and chief executive of the nonprofit N Street Village, which runs the Patricia Handy shelter, said a woman at the facility was isolated at an off-site location maintained by the city after becoming ill. She later tested positive for the coronavirus, Stribling said, and those with whom she interacted have self-quarantined.

Tests are not being performed on residents without symptoms, Stribling said.

“The inside and out of why we don’t have more tests in our country sort of escapes me,” she said. “For whatever reason, they are not available unless people are symptomatic. It’s holding true for the women that we serve just as it has been at my doctor.”

Amanda Chesney, executive director of housing and homeless services for Catholic Charities of the Archdiocese of Washington, which runs the Harriet Tubman shelter and four other shelters in the District, said that “to just have less than a handful of cases across the system is pretty huge.”

“All hands have been on deck since the beginning of the month,” she said. “I think we’re doing a good job of staying on top of it.”

The Community for Creative Non-Violence didn’t return a request for comment.

Bowser said Wednesday that she wasn’t aware the city had used its powers to involuntarily commit any homeless person to psychiatric facilities who might refuse to quarantine.

“I don’t believe that we have used it, but it certainly is a tool at our disposal,” she said. “It’s not something that any city official would want to engage.”

Fenit Nirappil and Darran Simon contributed to this report.