Polio may have been circulating in New York as early as April and the virus has been detected in wastewater samples more than 20 times, a Centers for Disease Control and Prevention (CDC) report reveals.
The agency released its first investigative report on the potential polio outbreak on Tuesday. The investigation comes as a response to the confirmation of a polio case in a man in his mid-20s in Rockland County, just outside of New York City, in June. Officials fear that there could be hundreds – if not thousands – of undiagnosed cases in the state.
While U.S.-borne cases are rare, the infected man had no recent travel outside of the country and had attended a large gathering eight days before the start of his symptoms. It is likely he caught the virus stateside. The man experienced paralysis and was hospitalized. He is now recovering at home.
The CDC reports that the virus has been detected in wastewater sampling in Rockland and nearby Orange County 20 times in samples gathered in May, June and July. A single sample from Orange County in April also had an incomplete sequence of polio, potentially indicating the virus was present as far back as four months ago.
Both Rockland and Orange counties have low vaccination rates – only 60 percent of people are jabbed by their second birthday, far below the 95 percent threshold set by the World Health Organization (WHO). The CDC deployed a team to Rockland to investigate last week and to assist in rolling out the vaccine to those in the community who had not yet received it.
Officials assure the public that a vaccinated person has little to worry about with the current outbreak. More than 90 percent of Americans are vaccinated by their second birthday – and many had to receive the shot to attend public school. There is no polio vaccine booster and vaccination in infancy provides protection for a person’s entire life.
The CDC reports that a Rockland County man who was confirmed to be infected with polio did not travel outside of the U.S. during the seven to 21 day window where symptoms usually appear. He did attend a local gathering eight days before symptom onset, though
Polio has been detected in the wastewater of New York City, Rockland County and Orange County in New York. While there has only been one confirmed case, sampling has detected the virus more than 20 times
‘The occurrence of this case, combined with the identification of poliovirus in wastewater in neighboring Orange County, underscores the importance of maintaining high vaccination coverage to prevent paralytic polio in persons of all ages,’ the CDC writes in its report.
The infected man initially experienced a fever, neck stiffness, stomach issues and limb weakness.
He was hospitalized, and a stool sample later confirmed that he had a case of vaccine-derived polio.
This form of the virus comes as a result of the oral poliovirus vaccine (OPV). The vaccine delivers a person a live version of the virus. While the body will usually kill the virus – generating antibodies – on some rare occasions the recipient will be infected.
The OPV is no longer used in the U.S., instead having been replaced with the inactivated polio vaccine (IPV) which is delivered via injection.
Some developing nations still use the OPV because it is easier to access and activates antibodies faster than the IPV, though.
Officials have not yet determined how this man was exposed to vaccine-induced polio.
Paralytic polio often takes between seven to 21 days for an infected person to feel symptoms. The man had no travel outside of the country during that period.
He did attend a large gathering of some sort eight days before symptom onset, though, which officials speculate could have lead to the exposure.
The CDC warns that only around one-in-every-1,900 polio infections in unvaccinated persons will result in paralysis – meaning there are potentially thousands of undiagnosed cases in the local community.
Common symptoms of polio include high temperatures, extreme fatigue, headaches, vomiting, stiff neck and muscle pain
‘Based on earlier polio outbreaks, New Yorkers should know that for every one case of paralytic polio observed, there may be hundreds of other people infected,’ Dr Mary Bassett, the state’s health commissioner said last week.
A local Rockland official warned the real case figures in the Empire state are likely in the thousands.
‘There isn’t just one case of polio if you see a paralytic case. The incidence of paralytic polio is less than one percent,’ Dr Patricia Schnabel Ruppert, health commissioner for Rockland County, told BBC.
‘Most cases are asymptomatic or mildly symptomatic, and those symptoms are often missed.
‘So there are hundreds, perhaps even thousands of cases that have occurred in order for us to see a paralytic case.’
After the discovery of this first case, the CDC launched surveillance for the virus in Rockland County and other local communities.
Wastewater samples were already being collected by local officials as part of COVID-19 surveillance, allowing the agency to track backwards to find older traces of the virus.
The CDC says that for every 1,900 cases of polio in an unvaccinated person, only one person will show symptoms of paralysis (file photo)
A total of 260 samples from Rockland and Orange counties were tested. Of that group, 13 samples from Rockland and eight from Orange were found to have traces of the virus.
One Orange county sample from as far back as April had an incomplete sequence of the virus. This means that it may, or may not, be linked to the Rockland County case.
In the time since the conclusion of this report on August 10, New York City officials confirmed the discovery of polio in wastewater surveillance as well.
‘The risk to New Yorkers is real but the defense is so simple — get vaccinated against polio,’ Dr Ashwin Vasan, the City’s health commissioner, said in a statement.
‘With polio circulating in our communities there is simply nothing more essential than vaccinating our children to protect them from this virus, and if you’re an unvaccinated or incompletely vaccinated adult, please choose now to get the vaccine.
‘Polio is entirely preventable and its reappearance should be a call to action for all of us.’
New York City has a vaccination rate of 86 percent. While better than Rockland and Orange counties, it still falls short of the 95 percent threshold set by the WHO.