This story was originally published by ProPublica.
US public health agencies generally don’t test wastewater for signs of polio. That may have given the virus time to circulate silently before it paralyzed a New York man.
About a month ago, British health authorities announced they’d found evidence suggesting local spread of polio in London.
It was a jolt, to be sure. The country was declared polio-free in 2003.
But at least no one had turned up sick. The proof came from routine tests of sewage samples, which can alert health officials that a virus is circulating and allow them to intervene quickly. Based on genetic analysis of those samples, officials in the United Kingdom moved to protect the city’s children by reaching out to families with kids under 5 who hadn’t been fully vaccinated.
Polio’s first appearance in almost a decade in the U.S., confirmed
late last week by health officials in New York, would play out quite differently.
In the U.S., public health agencies generally don’t test sewage for polio. Instead, they wait for people to show up sick in doctor’s offices or hospitals—a reactive strategy that can give this stealthy virus more time to circulate silently through the community before it is detected.
In New York, the first sign of trouble surfaced when a young man in Rockland County sought medical treatment for weakness and paralysis in June. By the time tests confirmed he had polio, nearly a month had passed.
Because the majority of polio infections cause no symptoms, by the time there’s a case of paralysis, 100 to 1,000 infections may have occurred, said Dr. Yvonne Maldonado, a professor of pediatrics at the Stanford School of Medicine who chairs the American Academy of Pediatrics’ committee on infectious diseases.
“You’re already chasing your tail if you’re going to wait for a case to show up,” she said.
Only after the case was identified did New York health officials start the sort of surveillance the British did, testing wastewater samples from Rockland County and beyond to help determine if the virus is spreading and where. Like many parts of the U.S., New York already was collecting sewage and analyzing it to track the spread of COVID-19. Health officials say they’re now testing stored samples for signs of polio. They say they’ve detected polio in a few Rockland County samples but need to analyze more to understand what the initial results represent.
For decades, the cost of doing wastewater surveillance for diseases like polio pretty clearly outweighed the benefit.
High U.S. vaccination rates, topping 90%, made the risk of such diseases incredibly low, though there have long been pockets of population in which rates are far lower. Rockland County, a suburban area northwest of New York City, is one such place. It suffered an extended outbreak of measles
, another vaccine-preventable disease, in 2018 and 2019 that was largely concentrated in its Orthodox Jewish community, where many opt out of vaccines. Several news organizations have reported
that the polio patient is a member of that community.
Nationally and globally, there are signs that the pandemic has opened up new vulnerabilities to diseases long in retreat. Routine immunizations have been hindered by a host of obstacles, including COVID-19-related lockdowns and growing vaccine resistance stoked by misinformation and politicization. A recent analysis by UNICEF and the World Health Organization showed that the percentage of children worldwide who received all three doses of the vaccine against diphtheria, tetanus and pertussis — a measure of overall immunization — dropped 5 points between 2019 and 2021 and that measles and polio vaccinations fell, too. The organizations say that’s the largest sustained decline in childhood vaccinations in the roughly 30 years they’ve been collecting data. Continue Reading…