At 1:30 p.m., some in line had already been waiting for more than four hours. Erin Dunn, 43, from Bristol, had arrived at 9 a.m. and was getting more and more tired. As a retired nurse, she understood the stress staff had to undergo, but began to experience symptoms after likely exposure to the virus.

“I could go to sleep now,” she said.

What she wanted was more information. No one had told him how long the wait would take or what the process would be. Messages left for Genesys Diagnostics on Wednesday were not resent.

Grace Bianchi, 63, had already visited the New Britain site earlier in the morning. People there were going mad and going through barriers, she said, and she and her husband were told to leave and come to the Bristol site instead.

“I had no idea I had to have lunch and dinner in my car,” Ms. Bianchi said, scanning seven more rows of cars in the parking lot. She was due to take a test to return to work next week.

“It’s ridiculous,” she said. “Workers should come first. “

She and her husband were not tested until 3:30 p.m.

There is no evidence that protesters and threats slowed down the country’s mass vaccination campaign. A spokesperson for the National Sheriffs’ Association, Patrick Royal, said Wednesday his group had not heard of widespread cases of violence at testing sites across the country.

Adele Hassan contributed reports.