Dodger Stadium in Los Angeles was the biggest COVID-19 testing site in the United States, with the ability to test over 10,000 people each day. But two weeks into January, amid a chaotic and slow-moving COVID-19 vaccine rollout, the city shut down the site in order to convert it into a vaccination site. The city closed another testing site, as well, temporarily slashing government-run COVID-19 testing capacity by one-third.

It’s a pattern playing out across the country, in states like Florida, Nevada, and Illinois. Health departments are working with limited resources to fight COVID-19, and many had to make a choice: keep testing at the same level or focus on vaccinating. “We remain very concerned that there’s only so many resources to spread around,” says Lori Tremmel Freeman, the chief executive officer at the National Association of County and City Health Officials.

Even before vaccines were available, health departments struggled to stay on top of testing and contact tracing. “That was before the introduction of the vaccine, and that’s another very complex, layered, response,” Freeman says.

Collier County, Florida shut down all but one county-run testing site so that health officials could shift attention to vaccination. In November, there were four. Staffing was the main issue, says health department spokesperson Kristine Hollingsworth. “There’s only so much staff who can do testing and vaccination,” she says. The department is now offering testing one or two days a week. “There’s still a need for tests, and we do get questions about it,” Hollingsworth says. “Thankfully, at least in our county, there are other clinics and urgent care sites that have tests.”

On the other side of the state, the city of Jacksonville converted two testing sites to vaccination sites. Fort Lauderdale converted one site, which could handle around 1,000 COVID-19 tests per day. In Illinois, officials shut down the testing site at the DuPage County Fairgrounds outside of Chicago so that the health department could funnel support toward vaccines.

And in Clark County, Nevada, officials scaled back one of the main testing sites to three days a week before shutting down. That site was running between 600 and 1,000 tests per day, says Fermin Leguen, acting district health officer of the Southern Nevada Health District. “The reason for that is because we didn’t have the resources to be able to open a mass vaccination site,” he told The Verge. “It is a big challenge for any health department to be able to accomplish both at the same time at a high level.”

Leguen says that he hopes Clark County will be able to reopen the closed testing site at some point. “We call this a temporary decision, but it’s contingent on us being able to to get more personnel so we can keep offering the same level of testing.”

Pharmacies and health centers also offer COVID-19 testing across the country, so health departments aren’t cutting off all testing when they switch to vaccines. Department-run sites, though, are streamlined exclusively for COVID-19 tests and can process hundreds or thousands a day.

The relief bill passed by Congress in December included over $8 billion for vaccine distribution, and that funding could help local health departments scale their efforts to vaccinate people. “Maybe we can convert testing centers into testing and vaccination sites,” Freeman says. Testing sites are running smoothly in many areas, and departments could expand on infrastructure that already exists. A drive-through testing center, for example, could add lanes for vaccination without shutting down testing completely. “We’re not reinventing the wheel, we’re taking advantage of what’s already been done,” she says.

The additional funding is welcome but is coming too late for health officials who are trying to jump-start their vaccination programs using their existing budgets. “Those resources were needed six months ago to help set up the systems,” Freeman says. “We’re just totally scrambling to play catch-up here.”

For now, in many departments, that has meant letting testing slip down the priority list. Testing is still critical to help identify people who may be transmitting the virus, Leguen says. But when weighing the two, the department believes that vaccination has a higher value for the community. “I will give preference to vaccination because we want to protect as many people as possible,” he says. “The sooner the better.”