Health leaders across the region this week were making plans to give booster shots of the coronavirus vaccine to millions of residents, in light of the Biden administration’s announcement that additional doses will be offered starting next month.

Burlington County was looking at potential sites for additional vaccine clinics, its health director said, and was waiting to hear whether New Jersey will bring back any of the mega-sites that vaccinated hundreds of thousands of people during the initial rollout.

Philadelphia, meanwhile, expects to use its existing clinics to administer boosters until at least late November — when more of the general public becomes eligible for the third dose — and a spokesperson said the shots should remain readily available, even for walk-ups.

Bucks and Camden Counties plan to offer boosters at several health department clinics, spokespeople said; Camden will offer them at pop-up sites, too.

With a vaccine supply far more plentiful than it was during the initial rollout, and with clinics in operation for eight months now, officials said they aren’t worried about the logistics of getting shots into people’s arms this time around.

“In terms of rollout, the infrastructure is in place now. That’s a good thing,” said Simon Haeder, an assistant professor of public policy at Pennsylvania State University who has done research on vaccine hesitancy and access.

But some, including Haeder, are concerned, they said, about the effect the booster shots will have on vaccine hesitancy, even though there’s growing evidence of the vaccines’ safety and effectiveness in preventing severe illness.

“We are definitely worried about that,” said Philadelphia spokesperson James Garrow. “People have been expecting that the vaccines are a forever solution and a silver bullet to this pandemic.”

“Because of that some believe that the imperfect protection afforded by the COVID vaccines is useless,” he added, “but that’s simply not the truth.”

» READ MORE: Coronavirus spread is high and hospitalizations are rising across the Philadelphia region

As the highly transmissible delta variant spreads across the country, overwhelming hospitals in other states, the Biden administration announced the booster shot campaign Wednesday, days after health officials had recommended moderately and severely immunocompromised people receive a third shot of the two-dose Moderna and Pfizer vaccines. The shots’ effectiveness in protecting against mild infection from the delta variant may fade beginning six months after the second dose, according to several new studies. The White House coronavirus response said they worried protection against severe infection could also diminish over time, as it has in other highly vaccinated places that are grappling with delta.

Starting the week of Sept. 20, booster shots are set to be offered nationwide, eight months after the second dose. That means health workers, nursing-home residents and staff, seniors, and people with certain health conditions — all of whom were among the first group to be eligible for vaccines early this winter — will be in the front of the line.

Some of the country’s leading scientists and public health experts criticized the plan, saying the data doesn’t support the need for boosters for the general public at this time. The announcement sent the wrong message, some national experts said, about the effectiveness of vaccines in preventing moderate and severe infection.

It also came at a time when the country and the region are trying to persuade more people to begin the vaccination process and to return for their second shots of the two-dose vaccines, which experts say are needed to provide the most protection. As of Friday, 54% of Pennsylvania’s total population, including children under 12 not yet eligible for shots, and 60% of New Jersey’s were fully vaccinated, according to the New York Times. Hospitalizations are rising in the area, too, with most patients being unvaccinated.

» READ MORE: In Philly’s least-vaccinated zip codes, fighting the delta variant is a game of catch-up

Stanley Weiss, a physician and professor at Rutgers New Jersey Medical School, said the takeaway from the booster shot announcement should be that vaccines work.

“The data is incredibly clear from innumerable studies from around the world that vaccinations work to decrease the chance of infection and to dramatically decrease the chance of serious infection,” he said. “The fact that we now need to deal with the delta variant and other variants … makes it appropriate to be extending vaccination.”

Gearing up for another rollout

Local health departments are getting a trial run for the booster shot campaign, albeit one much smaller in scale: About 800 moderately or severely immunocompromised people have received third doses through Philadelphia, Chester, and Bucks Counties’ health departments, spokespeople said. Gloucester County began offering third shots this week, and in the coming days, Montgomery and Camden Counties are set to do so as well.

The booster shot rollout, however, will require even greater coordination. Pennsylvania and New Jersey have not yet announced any specific plans. The Pennsylvania Department of Health said in a statement late Friday that it expects to use the existing network of 3,000 providers to administer booster shots, and advised residents to check their vaccination cards to see when they will be eligible.

Although the national campaign will formally begin late next month, most residents didn’t get their first and second shots until the spring. Since boosters are recommended eight months after the second dose, clinics are unlikely to see a surge in booster-shot recipients until early winter, Philadelphia’s Garrow said, giving officials more time to gauge demand and ramp up efforts as needed.

“We have learned a lot since the early stages of the vaccine rollout, have implemented improvements, and we will continue to review, assess, and make improvements if needed,” Chester County Health Director Jeanne Franklin said.

Delaware and Montgomery Counties are awaiting more information from the state, spokespeople said, but plan to roll out boosters using the same models they did for first and second doses. In Montgomery County, a spokesperson said this includes online and phone registration systems, mobile clinics, and its homebound vaccine program.

“We believe that the situation will be better this time around since there is plenty of vaccine available to anyone who wants a third shot,” county spokesperson Kelly Cofrancisco said. “Much of the issue with the initial rollout was the scarcity of vaccine.”

In Burlington County, where officials are expecting about 65% of people who received a two-dose vaccine to return for a booster, health director Herb Conaway said he anticipates the issue now being less about vaccine supply and more about finding enough people to give the shots.

Officials there plan to expand the number of clinics run by the county and Virtua Health, sites that will need to have a high capacity, especially if the state doesn’t bring back the mega-sites, he said. And if the Pfizer vaccine receives full FDA authorization, which the New York Times has reported could be as soon as Labor Day, Conaway said he also expects “you’ll have vaccine-hesitant people come into the vaccination pool.”

“We could see a crush,” Conaway said. But “we can stand up [more] sites pretty quickly if we need to. We sort of know how to do this. We’ve had practice.”

More work to be done

The impending rollout of booster shots served as yet another reminder that the pandemic is far from over, officials and experts said, so more efforts need to be taken to address hesitancy, bridge partisan divides, and stress the continued need for proper masking and other safety measures. Announcing the booster shots and showing data, they said, is not enough.

Public health leaders should be more cognizant of their messaging, said Haeder, the Penn State professor, and the way their remarks could be interpreted in such a polarized political climate, where conservative news outlets — and their viewers, who are generally more likely to be unvaccinated — are quick to jump on any examples of what they see as “flip-flopping” or “backpedaling.”

» READ MORE: Some people’s minds are changing about the coronavirus vaccine. Here’s how doctors persuade them.

There also needs to be stronger bipartisan outreach, he said. Without it, he added, not enough people are going to get vaccinated and the pandemic will continue to drag on.

“The ideal situation would be where President Biden and President Trump do an event and get the booster shot together,” Haeder said. “That would take the wind out of a lot of sails.”

With all the discussion about vaccines recently, leaders have spent less time discussing other measures that can provide protection immediately, said Weiss, the Rutgers professor and physician. People need to be reminded of the importance of wearing well-fitting face masks; more research should be done on whether other adjustments need to be made to air-conditioning and heating units in public spaces; and contact tracing must be ramped up, he said.

“What I hope people understand is that the pandemic continues,” said Burlington County’s Conaway. “The delta variant that we’re fighting now is one of many. And the longer it takes to achieve immunity through vaccination … the more likely we are to see these variants and the more likely, therefore, we’re going to need to adjust our vaccination program.”

“I hope people will understand,” he added, “the booster is just part of a continuum of the fight.”