The first case of polio in the U.S. since 2013 has been identified in an unvaccinated individual in New York’s Rockland County, health officials announced on Thursday.
The individual developed paralysis, Beth Cefalu, Rockland County’s director of strategic communications, tells STAT News’ Helen Bramswell.
Jennifer Nuzzo, a Brown University pandemic researcher, told Mike Stobbe of the Associated Press (AP) that the case should be a wake-up call for people who are not vaccinated against polio. “If you’re vaccinated, it’s not something you need to worry about,” Nuzzo says. “But if you haven’t gotten your kids vaccinated, it’s really important that you make sure they’re up to date.”
Walter Orenstein, a polio expert at Emory University, tells STAT News, “If there are unvaccinated communities, it can cause a polio outbreak. The inactivated polio vaccine we have is very effective and very safe and could have prevented this.”
According to the CDC, polio is a life-threatening disease caused by the poliovirus. While about three in four people infected with the virus will not experience any symptoms, about one in four experience flu-like symptoms, and about one in 200 experience paralysis or weakness in the arms, legs, or both. While vaccination prevents the disease, no treatment exists for polio, writes the Washington Post’s Lena H. Sun and Mark Johnson.
The New York State Department of Health said in a statement that the unvaccinated individual was infected with a type of the virus spread by someone who received an oral polio vaccine that has not been used in the U.S. since 2000, but is still used in other countries. Cefalu tells STAT News that while officials are still investigating, they do not believe the individual recently traveled to a country where this type of the virus is spreading.
If the unvaccinated person did not contract the virus abroad, “that would indicate someone else inadvertently imported the virus, suggesting there may be additional undetected transmission,” writes Stat News.
Polio, which mostly affects children, used to cause thousands of cases of paralysis in the U.S. every year, but the number of cases fell dramatically once vaccines became available in 1955, per the AP. Fewer than 100 cases were detected in the U.S. in the 1960s and fewer than 10 in the 1970s.
The oral vaccine given in some other countries contains live but weakened virus that can spread from child to child in places with poor hygiene, immunizing others, per Stat News. But in very rare cases, the weakened virus can mutate as it spreads and cause paralysis in unvaccinated people, Amesh A. Adalja, senior scholar at Johns Hopkins Center for Health Security, tells the New York Times’ Hurubie Meko. The injected vaccine the U.S. contains inactivated virus and cannot cause paralysis, per Stat News.
According to Rockland County Executive Ed Day, the individual is no longer contagious, reports the Times. Per the publication, Patricia Schnabel Ruppert, the county’s health commissioner, said in a news conference that the department is surveying the individual’s family and close contacts to assess risk to the community.
The virus is very contagious and typically enters the body through the mouth from hands contaminated with fecal matter from an infected person, writes the Washington Post. It can also spread via respiratory transmission and oral to oral transmission, even by people who are infected but asymptomatic.
Disruptions in vaccine delivery caused by the Covid-19 pandemic, as well as misinformation about and mistrust in Covid-19, have contributed to lower vaccination rates in children, reports the Times. Vaccine resistance has been prevalent in Rockland County in recent years, per the AP. Only 60 percent of Rockland County’s two-year-olds are fully vaccinated against polio, according to the Times, while 92.6 percent of children are fully vaccinated by the age of two nationwide.