Polio is a disease caused by the poliovirus. Polio can cause flu-like symptoms like nausea, headache, fever, and sore throat, usually in about a quarter of infected individuals. Around one in 200 people that are infected will get a more severe disease, and their illness can impact the spinal cord and brain, and may cause paralysis or death. The virus is spread through direct contact, or you can inhale it.
The CDC has long recommended that children get vaccinated for polio. Since 2000, children in the United States have been given the inactivated polio vaccine (IPV), which is administered as a shot in the arm or leg, depending on age. Some other countries still use the oral polio vaccine (OPV), which is considered to be very safe and effective. OPV is made from a live, weakened variation of the polio virus, a modified polio Sabin type 2 virus.
On some very rare occasions, however, the attenuated virus that is used in OPV can pick up genetic mutations that makes it virulent. This seems to have happened recently. Because vaccine hesitancy has become a problem in some communities, the mutated virus was then transmitted to another, unvaccinated person.
It's thought that a person who was vaccinated with OPV in another country transmitted infectious poliovirus to an unvaccinated young adult in Rockland County, New York. That unvaccinated individual then presented with symptoms of weakness and paralysis.
Clinicians and scientists can isolate the polio virus from infected individuals to determine whether a case derives from OPV.
Once the patient was identified, officials began wastewater surveillance to check for more poliovirus. It was then detected in eleven samples, which were linked to the case that had already been identified. This suggests that community spread is ongoing, and health officials are concerned. They are urging anyone who is not vaccinated for polio to get vaccinated immediately. Rockland County, New York has a low vaccination rate of about 60 percent.
Work by the Global Polio Eradication Initiative (GPEI) has also linked the Rockland County case to poliovirus detected in wastewater in London and Jerusalem, so it might be far more widespread than we knew.
The treatments for polio can only relieve some symptoms. If polio causes paralysis, that becomes permanent, and there is no cure.
New York State Health Commissioner Mary Bassett noted that the virus has been detected in sewage, and that may show that a larger outbreak is occurring. “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,” Bassett said.
People who are vaccinated for polio should not be concerned.