In the early 1900s, up to 35,000 Americans a year were disabled by polio. The virus, which mainly spread during summer months, was finally tamed with a highly effective and widely embraced vaccine.
For decades, transmission had disappeared in the United States. Until now.
New York reported a confirmed case of paralytic polio in July, and wastewater surveillance showed the virus may have been circulating in neighboring counties since April.
Health experts are calling it a “wake-up call,” but they don’t think the single case or subsequent viral detection will lead to a countrywide outbreak akin to COVID-19 or monkeypox, as over 90% of the country’s young children are vaccinated against polio.
Experts, however, say pockets of unvaccinated people across the country may be at risk.
“What worries me is the communities where vaccination is suboptimal,” said Dr. Wafaa El-Sadr, professor of epidemiology and medicine at Columbia University Mailman School of Public Health. “It is in those communities where you’re likely to get spread rather than communities with coverage.”
Health officials announced on July 21 that a young adult in Rockland County, New York, had been diagnosed with polio in June. The person had never been vaccinated against the virus, officials said, and suffered paralysis as a result of the disease.
A report from the Centers for Disease Control and Prevention shows the case – the first transmitted within the U.S. since 1979 – came from a person who had taken an oral polio vaccine in a different country. A rare complication of the attenuated live vaccine, which has not been given in the U.S. in more than two decades, allowed the person to develop a mild case of polio and shed the disease.
Like every state in the U.S., New York requires children to get a polio vaccination before attending child care facilities and schools.
But in Rockland County, only about 60% of children under 2 received their recommended series of the polio vaccine, according to state data. The CDC report showed some zip codes have vaccination coverage as low as 37%.
“Ideally, you want more than 90% at minimum among children,” El-Sadr said.
Although data is inconsistent throughout the country, health experts say low vaccination rates aren’t unique to New York. There are likely other states with pockets of unvaccinated residents who could be vulnerable to the virus.
‘Tip of the iceberg’:New York health officials raise alarms over possible polio spread