Health officials in New York have once again detected poliovirus in wastewater from Rockland County, where a case of paralytic polio occurred last summer.

Wastewater samples from Rockland and several nearby counties were positive for poliovirus for months after the initial case was reported in July, suggesting widespread circulation of the virus in the region.

So far this year, officials have only detected poliovirus in one sample, which was collected from Rockland in February. Two samples from the county taken during March were negative. Before the detection in February, the last positive sample from the region was found in mid-December in Orange County, just north of Rockland. The last positive detection in Rockland was in October.

While the data doesn't suggest that poliovirus is again circulating widely in the region, health officials are wary that the virus could easily restart. Rockland has one of the lower vaccination rates in the state; as of August, only 60.34 percent of 2-year-olds in the county were up to date on their polio vaccinations. Some areas of the county have rates in the 50s.

Officials are concerned about the potential for international spread of polio to Rockland's sizable Jewish community during upcoming holiday travel.

"With increased travel expected between Rockland County and Israel over Passover, the County of Rockland reminds families there is a real risk of paralysis from the polio virus if you are unvaccinated," Rockland County officials said in a press release.

Israel's Ministry of Health has recently reported four polio cases in children in the northern part of the country. One of the cases was paralytic. The strain of poliovirus behind the paralytic case in Rockland last summer was linked to viruses spreading in London and Israel at the time.

In addition, Rockland officials noted that we are heading toward summer, when polio transmission historically peaks.

"Polio is preventable through the complete vaccination series. Our hope is that we will not see another case of paralytic polio as we did last summer. I urge all who are unvaccinated or are under-vaccinated to complete their series. This is important locally as well as for travelers," Patricia Schnabel Ruppert, Rockland's health commissioner, said.

Officials continue pushing for vaccination in parts of the county where anti-vaccine sentiments are high. They're offering free polio boosters at walk-in clinics, working with the Centers for Disease Control and Prevention to audit vaccination coverage at day cares and schools, and trying to improve vaccination messaging.

"It is our obligation to protect all our residents from these debilitating and potentially fatal diseases. The law requiring childhood vaccinations has been in place for many years for this very reason," County Executive Ed Day said. "I urge our residents to act now and protect yourselves, your family, and your community."

In addition to fighting back polio amid poor vaccination rates, Rockland has also found itself fighting measles. In 2019, the county faced a prolonged outbreak that led to an emergency declaration.