Polio was discovered in Rockland County wastewater 25 days before the patient developed symptoms, suggesting others were previously infected.
“The fact that we see it in the sewer 25 days earlier means it probably isn’t even the second case,” said Dr. Eisenberg.
People who have received three doses of the inactivated polio vaccine are well protected against the virus, but the virus poses a potential danger to unvaccinated people, including children who are too young to be vaccinated.
Nationally, the vaccination coverage against polio is relatively high. But there are parts of the country, including New York, where vaccination rates are much lower, and the pandemic has delayed childhood vaccination campaigns.
By July 2020, only 67 percent of Rockland County children under 24 months of age had received three doses of the polio vaccine, a figure that had fallen to 60 percent this month, according to the survey.
After the case was discovered in Rockland County, the local health department began a vaccination campaign, but the number of injections administered “wasn’t enough to significantly increase vaccination coverage,” the researchers reported.