When the Johnson & Johnson COVID-19 vaccine was approved for emergency use, health officials described it as a game-changer: A single-dose product that could get shots into more arms more quickly.

Homeless outreach organizations, especially, saw it as a way to get vaccines to their clients struggling to navigate challenges that make getting to a doctor tough.

Now, with that vaccine’s distribution paused as federal health agencies investigate reports of rare blood clots, some Philadelphia-area organizations that work with homeless residents said plans to vaccinate clients have been complicated. And this new hurdle comes at a time when many of these organizations are dealing with more clients than ever, as pandemic-related job losses have upended people’s lives and, in some cases, housing.

“This tenuous way of life is really very common,” said Susanne Johnson, associate medical director at Camden’s Project H.O.P.E. “It’s become even more common during the pandemic. We’ve created a society where people walk this razor’s edge between stability and complete ruin. And the difference could be a house fire. It could be losing a job.”

A number of homeless services organizations around the Philadelphia region have organized mobile vaccine clinics or planned special outreach to get more clients vaccinated. But they’d also been hoping to use J&J shots to make the job easier: days before distribution was paused, Liz Hersh, the director of Philadelphia’s office of homeless services, called the J&J vaccine “a godsend.”

Now, many organizations are rearranging or pausing plans as they await further guidance on the vaccines.

In Bucks County, Pennsylvania’s vaccine rollout plan -- which is separate from Philadelphia’s -- meant people living in homeless shelters were not eligible to get the vaccine until now, even though they are in close quarters, where there’s a higher risk of contracting COVID-19.

Julie Dees, the CEO of Family Service Association of Bucks County, the county’s emergency shelter, and her colleagues had been planning mobile vaccination events using the J&J shots, vaccinating people in shelters and those on the street. Now those plans are on hold, said Dees, who also is chair of the county’s vaccine work group for people experiencing homelessness.

At Camden’s federally qualified health center Project H.O.P.E., which runs a clinic for people experiencing homelessness, the halt could change plans for a May 15 community vaccination day. They had planned to invite people to walk up for J&J shots, no preregistration required, said Johnson.

At the same time, she said, the clinic hoped to attract potential new patients who could benefit from regular care at the clinic.

Many of Project H.O.P.E.’s patients are experiencing homelessness or have mental health issues and are living in group homes. They don’t have transportation to reach the megasites that have been administering the highest volume of doses in the state. And as commercial development has begun to transform downtown Camden, day services for drug treatment, mental illness and other services have declined or moved farther from the city center, making it harder to stay in touch with some of Project H.O.P.E.’s transient patients, Johnson said.

Project H.O.P.E. also serves a large number of people who aren’t sleeping on the street, but who might be crashing with friends or family temporarily. Many also work jobs that make it hard to get to an appointment during 9-to-5 hours, and don’t have a car to get to vaccine sites with weekend hours.

That further underscored the importance of using the one-shot Johnson & Johnson vaccines for those who do show up for care.

“If you don’t have stable housing, the likelihood that you’re going to come back for your second dose is going to be low,” Johnson said.

Now, with the pause on J&J shots, she said she feared vaccine hesitancy would increase.

In Philadelphia, officials said their plans to vaccinate the city’s homeless population were similarly complicated. “We were trying to reserve the Johnson & Johnson vaccine for people that might have difficulty coming back for two doses. So someone who was homeless on the street or someone who was homebound, couldn’t come in, we were trying to use that for,” said Thomas Farley, the city’s health commissioner. “It will make it more complicated to reach those people with two doses. We will have to adjust.”

If the pause goes on longer than expected, “we’ll do the best we can with one of the two-dose vaccines,” he said.

Neal Goldstein, an assistant research professor of epidemiology at Drexel University’s Dornsife School of Public Health, said that if J&J shots are pulled entirely from the nation’s vaccine arsenal, local public health departments should use the two-dose vaccines they already have to continue vaccine outreach in underserved communities.

“What do we do if we don’t have a one-shot vaccination? We just have to shift to using our other vaccination supplies,” he said. Even if a patient who’s harder to reach misses their second appointment, they will at least have some protection from the virus.

“I’d rather have incomplete vaccination than no vaccination,” he said.

While the two-shot regimen can be a barrier for some, at least one Philadelphia clinic has seen more people than expected return for their shots.

The Hub of Hope, the drop-in center in Suburban Station for people with housing issues, has been giving clients Pfizer or Moderna two-dose vaccines for months. They’ve seen an 80% return rate for the second shot, said Ivel Morales, the center’s medical director, in an interview last week.

“It doesn’t necessarily mean people come the day of their appointment,” she said. “Some come by and realize, ‘Oh, maybe I’m due!’ A lot of people were saying we should be doing the J&J shot. But we have an 80% return rate. It’s been much more successful than what we anticipated.”

Hub of Hope participants who got their vaccines at the Suburban Station stop said they trusted doctors there and had been excited to get their shot. They ranged from former clients who had since entered permanent housing to current shelter residents hoping to protect themselves and those they lived with from the virus.

“I never received a vaccine -- I was really particular about it,” said Michelle Bernard, 57, a Hub of Hope regular who got her second vaccine dose earlier this month. “But when I heard that it would be at the Hub of Hope, I said, ‘Go for it.’ Because I know I’m safe.”