DOVER, Del. (AP) — Delaware residents who are not currently eligible for the COVID-19 vaccine nevertheless received it at a mass vaccination event attended by Gov. John Carney, according to state officials.

The Division of Public Health said after Saturday’s vaccination event that screening would be “tightened” for vaccination events on Sunday and Monday, and those not in the state’s top-priority phase 1A, which is limited to health care workers and long-term care residents and staff, might be turned away.

It’s unclear how ineligible people were allowed to get the vaccine at Saturday’s drive-thru event at the Division of Motor Vehicles in Dover. Carney’s office had billed the event as a “Phase 1A Vaccination Clinic” as “Delaware ‘sprints’ to vaccinate individuals in Phase 1A.”

Officials have previously said that phase 1B, targeting front-line essential workers and people 65 and older, was expected to begin by the end of the month.

“We are still in Group 1a and the vaccines today were supposed to be given to health workers and first responders,” House Speaker Pete Schwartzkopf said in a Facebook post Saturday.

“A few people went through and should have been challenged but weren’t primarily because the staff doing the vaccination is made up of volunteers and they didn’t have access to a database to verify that they were first responders,” Schwartzkopf added. “Others arrived and got vaccinated because friends ... called them or posted online and told them to come get vaccinated because they had gotten theirs.”

Near the end of the event, the number of first responders arriving had slowed down, so a decision was made to try to get some people 65 years or older to come through,” Schwartzkopf said in the post.

“The organizers wanted to use all of the vaccine they had so they dipped down into group 1b and had Modern Maturity bring about 100 seniors over,” he wrote, referring to a senior community center in Dover.

Andrea Wojcik, a spokeswoman for the Division of Public Health, said in an email Sunday that to test the logistics and process for vaccinating the 65 and older population once the state moves to Phase 1B, and to use available vaccine doses, DPH asked a small number of organizations with senior citizen members to come to drive-thru vaccination events being held in Dover through Monday.

Wojcik said in a subsequent email that the technology being tested was for registering and managing vaccinations at drive through clinics.

“Misinformation was spread by social media and word of mouth that caused some people to come out and go through the line,” she wrote.

Wojcik did not explain why officials did not announce the testing ahead of time or when they invited senior groups to attend.

“The select group of 65 and over was included to help with a test of a technology project that will be used to register and process vaccinations in the next phase,” Wojcik wrote. “Also, due to increased risk of allergic reactions and more involved medical history, it may take longer to process a person aged 65 or older through the vaccination process, including potentially longer observation times after the vaccine is administered, and DPH wanted to review that effect on the drive-through clinic process, again in preparation for the next phase.