The Biden administration’s health and housing departments have formed a partnership to bring coronavirus vaccines and tests to public housing and homeless shelters, part of an effort to promote access to the protective shots and foster confidence in them.

Speaking Wednesday at a community health center and housing-assistance organization in Southwest D.C., Health and Human Services Secretary Xavier Becerra and Housing and Urban Development Secretary Marcia L. Fudge said their agreement is a strategy to help defeat the pandemic by seeking out low-income people where they live.

“We are going to go where you are, and we are going to invest in you. . . . I don’t believe Zip codes were ever meant to tell you what the status of your health would be,” Becerra said. He acknowledged the nation’s neighborhoods that are home to low-income Americans tend to be less healthy and — this year — have lower coronavirus vaccination rates.

The two federal departments are launching the project as the largest mass vaccination campaign in U.S. history — widely regarded as a path out of the worst public health crisis in a century has been pivoting. In the early phase of the effort, which began in December, vaccine supplies were scarce. More recently, doses have become plentiful, but the pace of people getting shots has been slowing.

President Biden said this week that the country should aspire to have 70 percent of adults vaccinated with at least a first shot by July 4. But he and members of his administration have acknowledged that the work from here will be more difficult, as the vaccination campaign increasingly must focus on reaching people less eager to get one of the three vaccines authorized for emergency use — or less able to reach a place dispensing them.

The project falls under an executive order Biden issued in January, on his second day in office, to “prevent and remedy differences in covid-19 care and outcomes” in communities of color and other places where residents have scarce access to health services.

The pair of Biden Cabinet members spoke at Community of Hope, which runs three health clinics in the District and five housing programs for families who are homeless or on the brink of losing where they live.

Kelly Sweeney McShane, the organization’s president for two decades, noted that the District’s Ward 8, site of the Community of Hope facility the secretaries visited, has half as many people vaccinated as Ward 3, which includes more affluent areas in Northwest Washington.

Of the city’s approximately 1,100 deaths from covid-19, the disease caused by the virus, Ward 8 accounts for more than any other part of the city, with 209, compared with 56 deaths in Ward 3, according to the District’s pandemic surveillance figures.

The nation’s capital is a microcosm of the uneven toll the pandemic has taken in the country. Vaccination rates are lagging in many underserved communities because of difficulty accessing the shots and wariness about their safety and effectiveness among some communities of color.

Fudge said that, from speaking with tenant associations in low-income housing, “We know if we can get to the people, they will get the shots, most of them.”

A letter, signed last week by Becerra and Fudge, urges federally funded community health centers to collaborate with HUD housing programs to vaccinate their residents. According to HHS estimates, the goal is to involve perhaps 200 health centers nationally.

HUD estimates the efforts will reach 7,500 public housing properties and about 6,700 homeless shelters, as well as more than 6,000 other types of multifamily housing.

The project will be funded through the American Rescue Plan Act, a pandemic relief bill that Congress passed in March. HHS officials said they could not yet say how much it will cost.

The agreement between the two departments calls for outreach efforts to encourage people to get coronavirus tests and vaccinations. Becerra and Fudge said trusted members of local communities, including religious leaders and sports coaches, will be enlisted to build confidence in the safety and usefulness of the vaccines.

The agreement also involves help with scheduling coronavirus tests and vaccination appointments. Fudge pointed out that people who are poor or homeless may have relatively little ability to sign up for appointments online or to see opportunities for testing or vaccination on social media.

And it will set up vaccine clinics in public housing developments, homeless shelters, properties that HUD helps or insures, and sites where homeless people live outside shelters.

It also will provide transportation to vaccine clinics, including for people who are not fully mobile.

And it is designed to help people find sources of medical care.

The Washington Post’s vaccine tracking shows that more than 148 million people in the United States have received at least one dose of a coronavirus vaccine, accounting for nearly 45 percent of the population.

“There’s a great amount of work to be done,” Becerra said. “We have to show folks they can have faith — not just in people, but in the government.”