The scene in Rockland County on Friday morning might well have been from a time capsule: residents rolling up their sleeves and getting vaccinated for polio, the highly infectious and sometimes fatal disease that has made an unexpected appearance in New York City’s suburbs.
The sudden interest in such inoculations came a day after the county authorities announced that a local adult, unvaccinated, had tested positive for the disease. The case prompted alarm from local officials and residents, some of whom couldn’t remember whether or not they had received the vaccine, which has been widely available since the 1950s.
Among them was Todd Messler, 64. He was one of 18 people who received shots at a pop-up clinic set up by the county health department in Pomona, N.Y., about 35 miles north of Midtown Manhattan.
“It hurt like hell, but I feel better,” he said. “It’s definitely the way to go.”
On Friday, state and county health officials were investigating the case, interviewing immediate family members of the patient and urging immunizations for anyone among the general public who had not received one.
Bryon Backenson, the director of the Bureau of Communicable Disease Control at the state Health Department, said that there was no indication yet of additional cases, though he noted that the state was trying to acquire as many samples as possible to test and was checking wastewater for signs of the virus.
Officials were also trying to spread the word about the seriousness of infection, as “people are not familiar with polio,” Mr. Backenson said, noting that he himself was not exactly conversant with it.
“The last real polio case I saw in a person is probably pictures of F.D.R.,” he said, referring to the Depression-era President Franklin D. Roosevelt. “I think for a lot of people, they don’t necessarily understand the gravity of what polio actually is.”
It was still not clear exactly when or where the patient had contracted the disease, though health…