If you live outside Chicago and you’re hoping to get a COVID-19 vaccine at the United Center, you’ll have to wait – at least for now.

Illinoisans who aren’t Chicago residents were suddenly blocked over the weekend from booking COVID-19 vaccine appointments at the West Side sports arena.

But after a confusing back-and-forth among government officials, it emerged Monday that non-Chicagoans will have access to United Center appointments again soon, though it’s not clear when.

The federally-run site on the West Side first allowed any senior citizen eligible for the vaccine to sign up. But after seeing more than 60% of appointments go to people outside of Chicago since registration began last week Thursday, government officials on Sunday abruptly announced that only Chicagoans would be able to sign up. Besides vaccinating people at least 65 years old, they expanded eligibility to those 18 and older with underlying medical conditions.

“This site was located in the City of Chicago where it would be in close proximity to the most vulnerable populations in the city,” Democratic Gov. JB Pritzker and the Federal Emergency Management Agency announced in a statement on Sunday. “The United Center site is a part of the Biden Administration’s strategy to focus additional effort on particularly vulnerable communities. This site was selected, and an additional allocation was made available to the City, to achieve this goal.

“Based on the early registration data, it became apparent this was not occurring, leading FEMA to provide additional guidance related to the site to better target communities hit hardest by the virus, including ones surrounding the vaccination site on the city’s West Side,” the statement reads.

The United Center location is managed by the federal government and provides vaccines in addition to the allotment already earmarked for Chicago and the rest of Illinois.

During various news conferences and calls with reporters on Monday, politicians sought to play damage control to explain the confusing and frustrating situation.

Pritzker said FEMA on Friday sought to limit the United Center vaccine to only those Chicagoans who live in certain zip codes, attempting to focus its efforts on vaccinating people of color who qualify, including those with serious underlying health conditions.

But at that point, many people — including those who live in the suburbs — already had appointments at the United Center.

“FEMA came late in the game here, right, and decided they wanted to change things,” Pritzker said Monday. “As you can imagine, there’s technology involved in this, there’s decisions that need to be made about, ‘Well, if we’re going to exclude other parts of the state like the collar counties, how are we going to serve them?’ It took a little while for the city of Chicago, FEMA and the state to come to some understanding of what the best way to move forward was.”

The final discussions came down on Sunday morning, just hours before the change was made to allow only Chicagoans to book United Center appointments online or through a call center.

“The decision was made to pivot and make sure that the city of Chicago was getting the lion’s share of those appointments,” Chicago Mayor Lori Lightfoot said at an unrelated news conference Monday.

After weekend talks over who can get vaccinated at the United Center, FEMA also agreed to coordinate mobile vaccination sites for people who live in the collar counties, Pritzker said.

Chicago’s Public Health Commissioner, Dr. Allison Arwady, sought to clarify the situation with a hastily called press call Monday just after noon. She stressed that the United Center vaccination site is not, in fact, only for Chicagoans.

Rather, Arwady said that only Chicagoans are allowed to sign up for appointments right now. But she said there are appointments being reserved for residents who live in suburban Cook County and elsewhere in Illinois. There are also appointments being set aside for the most vulnerable Chicagoans based on their ZIP code, as well as for community organizations that will target outreach to people who have disabilities, for example.

“I know that that is disappointing for people who don’t live in the city of Chicago,” Arwady said. “That’s part of why I wanted to reinforce that there are a lot of appointments that are being really held for non-Chicago residents.”

Arwady would not say when and how those appointments would be made available. She also would not say how many total appointments are available at the United Center, and how many are for residents depending on where they live.

She said more details would be coming soon.

In a statement, a representative for the Cook County Department of Public Health, which oversees most of suburban Cook County, said the county is moving fast to strategize how best to allocate vaccine equitably at the United Center. But many details are still being worked out.

“The amount of vaccine and the timing will factor greatly in these decisions, so as we know more we can plan more precisely,” the statement said.

Arwady emphasized that vaccinating people 65 and older remains the top priority. She underscored how popular the United Center vaccination site is.

On Sunday afternoon when Chicagoans with underlying health conditions were suddenly able to book vaccine appointments, they filled quickly. There were 300,000 hits per minute, and 754 appointments booked per minute at the peak.

City Politics Reporter Claudia Morell contributed.

Kristen Schorsch covers public health, and Tony Arnold covers Illinois politics, on WBEZ’s government and politics desk. Follow them @kschorsch @tonyjarnold.