Inside Fairfax County’s government center one recent morning, elderly residents streamed in to get their first dose of the coronavirus vaccine, underscoring a problem that has vexed officials across the greater Washington region.

In a county of 1.1 million residents, where 26 percent of the population is Black or Latino, nearly everyone getting a shot was White.

Amid a vaccine shortage where savvier residents have snapped up online appointments, local officials are working to more evenly administer doses through such initiatives as mobile vaccination clinics and free rides to appointments.

So far, however, those efforts have had little impact, fueling concerns that the blue-collar workers and immigrants who have suffered the most during the pandemic will remain vulnerable to severe illness.

“A lot is at stake,” said Jeff C. McKay (D-At Large), chairman of the Fairfax County Board of Supervisors. “It makes it much more difficult to stop the spread of the virus because those people have to go to work. They live in communities where people are in close quarters, and they potentially are exposing others.”

Vaccination data broken down by race and ethnicity in the region has been incomplete, prompting Virginia Gov. Ralph Northam (D) this past week to sign emergency legislation that requires demographic information to be taken when doses are delivered.

Of the 947,000 Virginians who shared their demographic details while receiving vaccinations, 12 percent were Black and 5 percent were Latino, even though those groups make up 29 percent of the state’s population.

In Maryland, where African Americans and Latinos are 40.6 percent of the population, Black residents received 16 percent of the vaccine doses in cases where demographic details are known, and Latinos received 4 percent. The District reports that among vaccinated residents who shared their information, 17 percent are Black and 3 percent are Latino, despite the fact that those groups make up nearly 57 percent of the city’s population.

Some of the discrepancy may be due to the fact that some of the groups that are currently eligible for vaccinations — including teachers, firefighters and elderly residents in pricey long-term care facilities — tend to be predominantly White, local officials say.

But many health-care workers — including in nursing homes — are overwhelmingly people of color, which should help offset that disparity.

Officials say the poor showing is also due to a lack of Internet access in some households, limited transportation options for vaccine appointments and an array of untrue claims about vaccine safety that has fostered a sense of hesitancy.

Several efforts to reverse the trend are underway.

In D.C., Baltimore City and Prince George’s County, health officials and hospitals have started using mobile clinics to vaccinate elderly residents in public housing and apartment buildings in predominantly Black and Latino neighborhoods. D.C. officials also recently launched a pilot program to stage vaccine clinics inside neighborhood churches.

Montgomery County and the District prioritize residents of certain hard-hit Zip codes for vaccine appointments, and Montgomery is holding virtual town halls about vaccinations for African Americans and Latinos and enlisting community groups to distribute informational fliers outside ethnic grocery stores and other busi­nesses.

Fairfax also relies on community organizations and religious groups, and offers free rides to seniors who can’t make it on their own to the county government center, which serves as the primary site for first doses while neighborhood clinics handle second doses. But the service so far has not reached much of its intended audience.

John Niles, 77, who is White, was among the fewer than 30 people who had taken advantage of the free ride service as of Thursday.

Niles, who lives a short drive from the county government center, found out about the service on social media after his car died a few days before his appointment. While waiting in front of his house for his driver, the retired cellist marveled at how confusing the vaccination process has been so far.

“I’m lucky,” he said just as Barry Wickersham drove up in his SUV to ferry him to his appointment. “There is a lot of fear out there about this whole thing.”

Wickersham, whose nonprofit Shepherd’s Center of Fairfax-Burke contracts with the county for shuttle services for the elderly, said his organization has tried to service the Route 1 corridor in southeastern Fairfax, where many lower-income Blacks and Latinos live about 22 miles from the main government center.

But “we haven’t gotten much interest,” he said. “There is a certain distrust of organizations that are not them or their church.”

Fairfax health officials said they hope to boost interest in inoculations among immigrants and African Americans through virtual town halls that explain the safety of vaccinations.

During a recent session with Latino immigrants in the Herndon area, county epidemiologist Rene F. Najera encountered the anxiety that many undocumented immigrants have over a government-run vaccination program.

Some are convinced the vaccinations are unsafe, while others see an appointment inside a county government center as an invitation to get deported.

“This is good for all residents of the United States,” Najera told the group in Spanish. “When I say ‘residents,’ I don’t mean just legal residents.”

McKay said the county’s limited supply of vaccine — part of a national shortage that should be alleviated in coming months — means more aggressive initiatives, including mobile vaccine units, are likely to be “many weeks” away.

“We can’t go out with vaccines into the community and administer them until we can get through the list of people who have already preregistered,” McKay said, noting that there are 103,000 residents in the county’s queue for appointments. “If we were in those neighborhoods now, aggressively going after folks, we don’t have the vaccines to actually vaccinate them.”

Baltimore Health Commissioner Letitia Dzirasa said her city can’t afford to wait for its vaccine supply to increase.

African Americans in Baltimore, who represent 60 percent of the city population, have been slammed by the virus, representing the majority of the city’s covid-19 deaths so far.

But only 30 percent of vaccine recipients whose demographic information is known are Black, and 3 percent are Latino, according to the city Health Department.

In partnership with the Johns Hopkins University schools of medicine and nursing, the city recently launched mobile vaccination teams to inoculate elderly residents in predominantly Black and Latino neighborhoods.

Skepticism about vaccine safety has played a role in the low uptake rate, Dzirasa said. But, mostly, residents in those neighborhoods have told the mobile teams that they were confused by the process of registering for a vaccine appointment online.

“It can be a little bit challenging to navigate, even if you have access to the Internet, even if you’re technically savvy,” Dzirasa said.

So far, she said, nearly all of the residents who’ve been approached by the mobile teams have signed up for the vaccine.

In Montgomery County, council member Nancy Navarro (D-District 4) said she is worried about immigrants who work as nannies, part of an informal economy in the region that includes housekeepers and home contractors who regularly interact with people but are not yet eligible for vaccinations. Navarro said the state health department requires 100 doses per week to be set aside for licensed child-care providers in the county but does not account for the thousands who are unlicensed.

“Even when you say: ‘Okay come, and please make sure you preregister,’ the fact that they are not able to access the vaccine creates a real disconnect and a real problem,” Navarro said. “We’re a county with a lot of resources, and still it’s a challenge.”