DOVER — Emotionally, Karen Mclellan is “very happy and relieved” after having been vaccinated. Physically, her arm hurts a bit.

“I was extremely excited to be able to finally get the vaccine,” she said Sunday, a day after getting her first dose.

Ms. Mclellan was one of the many vaccinated this weekend, attending a drive-thru event at the Dover Department of Motor Vehicles. As an occupational therapist, she is part of Phase 1A that the state is currently “sprinting” to vaccinate, holding large scale events like the few this weekend, which can vaccinate up to 1,500 people each day, officials said.

But it wasn’t only those in Phase 1A who were able to get a taste of that excitement. To “test the logistics” the Division of Public Health opened vaccinations to those 65 and older, who are part of the state’s next phase (Phase 1B) on Saturday and Sunday.

Ms. Mclellan’s family was among those.

“I was extremely relieved for them,” she said. “I mean, I would have given my vaccine to them because they’re over 65 and have other conditions, so I think that was more exciting than even myself getting the vaccine, that they were able to get it.”

Andrea Wojcik, a spokeswoman for the Department of Health and Social Services, said in an email that the state doesn’t yet have the number of seniors who were vaccinated this weekend. Not all seniors received vouchers to the event, and only needed to present a photo ID, she said.

“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,” she said.

She added that, “due to increased risk of allergic reactions and more involved medical history” there may be a longer process for those aged 65 or older to go through the vaccination process.

That includes potentially longer observation times after the vaccine is administered, she said.

“ wanted to review that effect on the drive-through clinic process, again in preparation for the next phase,” she said.

The state posted online that organizers would be strengthening restrictions ahead of Sunday and Monday’s vaccination events, with only those in Phase 1A — health care personnel with direct contact with ill patients or infectious material, emergency medical services agencies, long-term care staff and long-term care residents — eligible to be vaccinated. Seniors, however, were again invited to be vaccinated Sunday, Ms. Wojcik said.

But confusion stemmed Saturday when some not in Phase 1A — and not 65 years or older — were able to be vaccinated and posted online that anyone could attend Sunday and Monday, state Rep. Pete Schwartzkopf wrote in a Facebook post.

“That is not the case,” he wrote. “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. Others arrived and got vaccinated because friends that I just described called them or posted online and told them to come get vaccinated because they had gotten theirs.”

Ms. Wojcik said in a statement that anyone not in Phase 1A or 65+ should “refrain from attempting to get vaccinated at the sites this weekend.” She did not respond to whether those outside of Phase 1A and not of 65+ age group were able to be vaccinated Saturday.

“Screening will be tightened for Sunday and Monday events and those not in those groups may be turned away,” the statement reads. “Vaccines remain in extremely short supply and are reserved for your friends and neighbors who need it the most.”