The New York State Department of Health has issued a health advisory after low levels of measles virus were detected in wastewater from a treatment facility serving parts of the City of Oswego and nearby areas. No clinical cases have been identified in Oswego County or surrounding regions at this time.
“Wastewater surveillance is an early warning system that helps us stay a step ahead of infectious diseases,” said State Health Commissioner Dr. James McDonald. “This detection does not mean there is an outbreak. It is, however, a timely reminder to make sure you and your family are up to date on the MMR vaccine and to keep an eye out for symptoms.”
Routine testing for measles in wastewater samples has been ongoing since October 2024 by the Department’s Wadsworth Center across various locations in New York State. The recent detection in Oswego came from one of two sites tested by WastewaterSCAN, a national commercial company. The Department was notified that a low level of measles virus was found in a sample collected in the City of Oswego, prompting further testing by both Wadsworth Center and WastewaterSCAN next week.
Wastewater surveillance allows for early identification of both symptomatic and asymptomatic cases within communities by analyzing untreated sewage entering treatment plants. This method has served as an important indicator for disease monitoring since 2022.
In Oswego County, about 87.8 percent of children under two years old are immunized against measles, leaving some residents susceptible to infection. Measles is highly contagious; even small groups with lower vaccination rates can allow it to spread. Approximately one in ten people with measles require hospitalization. Two doses of the MMR vaccine provide 97 percent effectiveness against measles, while one dose offers 93 percent protection.
Healthcare providers have been alerted and reminded to report any suspected cases immediately to local health departments.
Measles spreads through airborne transmission when infected individuals cough or sneeze, with the virus remaining viable in the air for up to two hours. Complications can include hospitalization, pneumonia, miscarriage, preterm birth, brain swelling, and rarely death; long-term effects may involve fatal brain disease developing years after infection.
Transmission can occur from four days before until four days after rash onset; symptoms typically appear seven to fourteen days post-exposure but may take up to twenty-one days.
Most people born before 1957 are considered immune due to likely exposure during childhood. Those unsure about their vaccination status should consult healthcare providers or local health departments.
The Department encourages all New Yorkers—especially those planning international travel or visiting areas experiencing outbreaks—to ensure they are fully vaccinated against measles.
Officials emphasize that this notification is precautionary as no clinical cases have been confirmed locally yet; additional testing will continue while public awareness efforts proceed.
