Poliovirus, which can cause permanent paralysis and sometimes even death, has been detected in New York City sewage, according to both the state and city health departments—who made the announcement in a joint press release on Friday.
The presence of the virus in waste water likely indicates that polio is circulating locally, among the general public, wrote officials. “For every one case of paralytic polio identified, hundreds more may be undetected,” said New York’s heath commissioner, Mary Bassett. And, although alarming, the finding isn’t a surprise, she added. Cases of the disease, once nearly globally eradicated, have been steadily emerging for months now.
A single case of paralytic polio, a severe form of the disease, was confirmed in Rockland County, NY on July 21. Wastewater samples later analyzed from Rockland and Orange Counties, both nearby New York City, collected earlier this summer and spring revealed poliovirus was more widely present there as well. Prior to these findings, no cases of locally transmitted (i.e. “wild”) polio had been detected in the U.S. since 1979.
Back in late June 2022, health officials in the United Kingdom also reported that they’d detected poliovirus in sewage. Previously the diseases had been declared locally eradicated there in 2003. One of the first hints of the current and growing apparent polio resurgence popped up with the case of a confirmed polio-related paralysis in a 3-year-old girl in Malawi in February.
As with covid-19, asymptomatic cases of the poliovirus can aid the disease’s transmission. According to the CDC, nearly three-quarters of people who get infected never display visible symptoms, and most of the remaining 25% experience flu-like symptoms including fever, sore throat, fatigue, nausea, headache, and stomach pain.
However, a small proportion of people develop a version of polio with much more severe symptoms that impact the nervous system and can develop into full-blown, permanent paralysis. The rate is about one in every 200 infections, according to the World Health Organization. From there, paralysis can lead to death, if a person’s ability to breathe is affected.
Once, polio was widespread, causing hundreds of thousands of confirmed cases worldwide, every year. Many were killed, and many more were left paralyzed—some severely enough to rely on iron lungs for their continued survival. Three polio survivors in the U.S. were still alive and relying on the medieval-looking machines, as of 2017. In the U.S. the worst recorded outbreak happened in 1952, paralyzing 21,269 people and killing 3,145 others.
But an extremely effective vaccine, developed by Jonas Salk, led to the disease being nearly eradicated over the course of just a few decades. Just 6 cases of the disease were reported in 2021. The polio vaccine is highly protective, and receiving all three doses is considered 99% to 100% protective, according to the CDC.
Vaccination has continued to be available, recommended, and widely required for participation in things like the public school system in the U.S.. However many parents have opted not to vaccinate their children anyway, amid the growing anti-vax movement.
Only about 60 percent of Rockland County children are being vaccinated against polio, and Orange County, NY has an even lower vaccination rate. In New York City, 86.2% of children between the ages of 6 months and 5 years have received all three doses of the polio vaccine. Yet in some neighborhoods, the children have much lower polio vax rates (as low as 56.3%), and thus are much more vulnerable.
Vaccinating children against polio is the most important thing people can do, to help prevent the diseases’ further spread and to stop the current outbreak. Further, most U.S. adults have already received the polio vaccine, but if someone hasn’t, it is never too late. Vaccination prevents infection, severe illness, and paralysis—and ultimately saves lives.