Pennsylvania could start receiving a COVID-19 vaccine as soon as next month, the state health secretary said Thursday, but the process of distributing the treatment promises to be a huge undertaking through much of the coming year.

“We’ll be rolling this out through the winter, the spring, and even the summer,” said Health Secretary Rachel Levine. “It could take a significant amount of time to vaccinate everyone in Pennsylvania.”

People in the state, she added, “will be wearing masks through 2021.”

The pharmaceutical companies Pfizer and Moderna have separately announced vaccines with an efficacy rate above 90% this month, creating hope for an end to a pandemic that has infected 11 million people and killed more than 250,000 nationwide. Both vaccines are pending approval from the Food and Drug Administration for emergency-use authorization, and four other vaccines have reached final trials. Developing effective, safe vaccines within a year is a medical marvel, health experts said, but it’ll take another extraordinary achievement to get those vaccines to everyone who needs them.

In the coming months, the region and the nation will face funding problems, a massive record-keeping project, a battle against misinformation, and hard choices about who gets first access to a limited supply of vaccine.

“This is going to be the nightmare of nightmares in terms of logistics,” said Bon Ku, a Jefferson University Hospital physician in testimony before Philadelphia City Council on Thursday.

And it’s going to require patience. The National Academies of Sciences, Engineering, and Medicine estimated in the initial phase of vaccine distribution there will be enough doses for 10 million to 15 million people, not enough to cover the approximately 16 million people eligible, primarily first responders and high-risk health workers. The first phase of vaccinations will also likely come to include some essential workers, the elderly, and those at greatest risk from the virus.

In Philadelphia alone, about 125,000 people could be eligible for vaccination in the first phase, said Caroline Johnson, the city’s deputy health commissioner. She doubted there would be enough doses for more than 25,000 people in the coming months.

“People are going to have to make some tough choices in letting this vaccine be administered to their staff and to some high-risk individuals,” she said.

She’s hopeful the vaccine will be readily available by summer, but “those first few months are going to be tough.”

Both city and state officials said they will need additional federal funding beyond the $200 million the federal Centers for Disease Control and Prevention has made available for vaccine readiness. Another $140 million is to be released in December. An additional $8.4 billion is likely needed from Congress, state health officials have said.

“There’s no real plan B … ,” said New Jersey Gov. Phil Murphy in a news conference Wednesday. “This is too complex and too expensive.”

Another hurdle: Pfizer’s vaccine has to be kept at minus-80 degrees Celsius for long-term storage. Freezers capable of maintaining that temperature are usually available only at bigger hospitals with research facilities and labs. Smaller hospitals in rural areas, though, will be at a disadvantage.

Levine also noted the need for a comprehensive education campaign to overcome public skepticism about the vaccine. The Star Trek-inspired name for the federal vaccine development project, Operation Warp Speed, was meant to convey urgency, but instead, public health experts said it also creates the impression researchers cut corners.

The vaccine is safe, health experts said, but a recent Gallup poll found only 58% of Americans were willing to get the shot. Health officials estimate that 70% of the U.S. population would have to be inoculated to relieve communities from lockdowns and social-distancing restrictions. Charles Cairns, a dean and senior vice president at Drexel University College of Medicine, estimated in testimony Thursday that closer to 80% of Philadelphians would need to be inoculated as soon as possible.

Levine said $340 million “is not enough to accomplish this prodigious task.”

Of the six vaccine candidates close to FDA approval, five, including Pfizer and Moderna, require two doses spaced out over time. That’s going to require health officials to maintain extraordinary records to ensure people receive the correct type of vaccine when they return for their second dose, said Angela Shen, a visiting research scientist at the Vaccine Education Center at Children’s Hospital of Philadelphia. If a person receives an initial shot of the Pfizer vaccine, but receives the Moderna vaccine in a follow-up visit, the treatment won’t work.

The CDC will distribute vaccines to states by population, and require reports on the vaccine’s use. A state won’t get new batches of the vaccine until it can report using every dose it received, Johnson said.

“They’re now asking public health to coordinate the largest vaccination response in 100 years,” Shen said. “We spent billions of dollars on development, but we have not spent billions of dollars on deployment.”

Reaching 70% inoculation nationally will require roughly 459 million vaccine doses.

The CDC won’t make a final decision about how to prioritize who gets the treatment until the FDA approves the current vaccine candidates, but it is expected to rely on a report from the National Academies of Science, Engineering, and Medicine, which puts first priority on health-care workers and first responders, followed by those most at risk of serious complications if infected.

Prioritizing gets more complicated in the subsequent phases of vaccine distribution.

In the city’s Black communities, the Department of Public Health expects to connect with community organizations, local pharmacies, and churches to provide information about the vaccine’s value and safety, and make it easy to get treatment.

“Lets make sure the vaccine is in those communities,” Johnson said, “at an access point they’re comfortable with.”

While some will be reluctant to be vaccinated, public health officials will have to contend with pressure from the opposite end, people desperate to receive the treatment.

“I think it’s going to be the Beanie Baby phenomenon,” said Paul Offit, a pediatrician and director of the Vaccine Education Center at Children’s Hospital of Philadelphia, referring to a 1990s craze for collectible stuffed animals. ”There’s going to be a limited edition vaccine.”

People who are able to work from home and are in good health may have to accept waiting a long time for the shot that may end their pandemic fears.

“I would like to say that people will get behind this,” said Molly Sauer, research associate with the International Vaccine Access Center at Johns Hopkins Bloomberg School of Public Health. “That question really reinforces the need for a thorough communication plan and making sure we have transparency about what the process is.”

Clearing the record: this story has been updated to correct how many people the vaccine doses distributed in phase one will be sufficient to treat.