The global pandemic isn’t the only current example of what happens when vaccine skepticism and misinformation infect the public. The global drop in childhood vaccinations is also the largest for three decades. On July 21, another virus with very effective vaccines against it appeared. A single case of polio turned up in Rockland County, New York—the first time any case of polio had been detected in the U.S. in nearly a decade. A man in his 20s who had recently been diagnosed with polio-related paralysis is the infected person, but his identity is not being released. The man had not been given polio vaccines.
One case of polio in one county can be a much bigger problem than it might seem. In 1979 the United States declared polio completely eradicated. Today, there is only one country in the world where the disease remains endemic. This is troubling because even one case of Polio made it to America.
“Many of you may be too young to remember polio, but when I was growing up, this disease struck fear in families, including my own,” said Rockland County Executive Ed Day in a statement to the media on July 21. “The fact that it is still around decades after the vaccine was created shows you just how relentless it is.”
The case may be alarming but the epidemiological pathway is not mysterious. A paradoxically, polio vaccine played a part in the transmission. There are two types of polio vaccines: an inactivated poliovaccine (IPV) or an oral poliovaccine (OPV). The IPV, as its name suggests, uses a killed poliovirus to sensitize the body’s immune system to the disease and prepare it to defend itself against a wild virus, should one be encountered later. The OPV uses an attenuated—or weakened—form of the virus to perform the same function. The big advantage of the OPV is that it can be administered easily and cheaply—simply with a few drops on the tongue—by nearly any health-care worker. You must inject the IPV.
The OPV is easy to administer and has been used in global polio-eradication efforts. However, there are some drawbacks. Rarely, the virus can return to the vaccine. This can sometimes lead to poliomyelitis in the person who has been vaccinated. Other times the person can be unharmed and still transmit the virus to others. The OPV is able to prevent far more diseases than it does. Global Polio Eradication Initiative estimates that there have been more than 16 million polio cases prevented from being caused by OPV over the past decade. The fact that any vaccine poses such a risk was the reason for the decision to stop using it in the United States in 2000, and instead administer the IPV.
The New York patient had genetic testing that confirmed the virus was vaccine-derived. Since the New York patient had never been outside the United States, epidemiologists believe that the virus may have been transmitted by an overseas recipient of the OPV.
All Americans need to stay current on vaccines, and get their children vaccinated. The U.S. Centers for Disease Control and Prevention reports that 92.6% (2-year-olds) have had their IPV shots. That’s a lot, but someone in the remaining 7.4% of unvaccinated children could be the next case, like that of the young man in New York. That’s a fate no parent wants for their child.
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