Health officials on Friday said they had found traces of polio virus in New York wastewater, suggesting the virus has been circulating among unvaccinated people in the US city of more than eight million.
“For every one case of paralytic polio identified, hundreds more may be undetected,” New York state health commissioner Dr Mary Bassett said in a statement.
“The detection of poliovirus in wastewater samples in New York City is alarming, but not surprising."
An adult polio case that resulted in paralysis was reported in a New York suburb in late July, the first case for the US since 2013. Afterwards, the virus was found in wastewater samples in two counties north of the city in June and July.
New York state officials say the counties have lower than average vaccination rates at about 60 per cent, suggesting the spread of polio has been among the unvaccinated.
Polio is a highly contagious virus that can cause paralysis and death in those infected. It can spread through contact with bodily fluids, faeces and people who are infected. Children are at highest risk.
It's preventable with a vaccine, which has led local health officials to call for New Yorkers to check on their vaccination status.
“The risk to New Yorkers is real but the defence is so simple — get vaccinated against polio," said New York City health commissioner Dr Ashwin Vasan.
The city says 86.2 per cent of children under the age of 5 in New York City have received three doses of the polio vaccine, which means 14 per cent are not fully protected.
Viruses that have not spread in years, particularly in non-endemic countries — such as polio and monkeypox — are showing a resurgence because of lower levels of immunity and delayed vaccinations due to the Covid pandemic.
Meanwhile, the US Centres for Disease Control and Prevention released a new guidance on Covid-19, which does not require unvaccinated people to quarantine for five days after being exposed and ends test-to-stay programmes in schools.
It also scrapped recommendations for two-metre physical distancing and testing of asymptomatic people with no known exposure to coronavirus.
The CDC says the changes are supported by Covid tools and treatments the US now has.
However, the new guidance received criticism by public health advocates who say the changes hurt high-risk or immunocompromised individuals, and risk complications if restrictions are needed to combat a new Covid-19 variant in the future.
