One Polio Case in the U.S. Is a ‘Public Health Emergency’

Throughout human history, poliomyelitis outbreaks have been a scourge of childhood and a parent’s nightmare. That is, until the development of polio vaccines in the 1950s. But, thanks to today’s climate of disinformation and misinformation about contagious diseases and the role of vaccines in keeping millions of people healthy, we may be seeing the start of a resurgence of this terrible disease.  

There is still no cure for polio. But vaccination, safe and easily available in the developed world and beyond, is an almost 100 percent safeguard against infection, for individuals and communities. 

Insidiously infectious and destructive 

Polio is extremely infectious. A person with polio can spread the virus even when asymptomatic. In unsanitary environments, it also spreads through contamination of food and water, through droplets expressed in sneezing and coughing, and through even a limited, one-time contact with the stool or other bodily fluids of an infected person. It can live in the intestines of an infected person for weeks. Polio can also spread if that infected person touches food or objects with unwashed hands, and then another person puts those items into their mouth. Of course, it spreads much more easily in communities with low vaccination rates. 

Most people who contract polio show no symptoms and don’t suffer irreversible physical damage. But the polio virus does attack the nervous system, resulting in incurable paralysis of the lungs or spinal cord in about 1 out of every 200 cases. About 5 to 10 percent of paralyzed people die due to their respiratory muscles becoming immobilized. Additionally, about one to five people per 100 who contract polio go on to develop meningitis, an infection of the brain and spinal cord. 

Even a child who recovers can later develop new symptoms of pain, weakness, or paralysis in the muscles as an adult. Some of these patients become paralyzed from this delayed reaction, known as “post-polio syndrome.” 

Vaccines to the rescue 

Vaccination against polio has proven itself over and over as the key life-saving factor. The development of vaccines followed one of the biggest outbreaks in the United States in history, in the late 1940s. Many communities regularly put people under quarantine at that time, travel and commerce slowed, and tens of thousands of people became disabled from polio every year. 

In the wake of this cascading tragedy, Dr. Jonas Salk completed work on the inactive, killed-virus vaccine in 1955, and Dr. Albert Sabin developed the live but non-virulent oral polio vaccine in 1960, opening the way for mass immunizations around the world. Just one year after Salk’s vaccine rolled out, the number of recorded polio cases dropped by more than 50 percent. Today, we have achieved near-eradication of the virus, with officials recording only six cases of “wild” polio virus worldwide in 2021. 

Doctors already declared the wild polio virus eliminated in the U.S. in 1979. The last known infection in Europe dates to 1998. In 2002, the World Health Organization confirmed Europe’s “polio-free” status, and in 2020, Africa was also declared polio-free.  

Yet despite regional vaccination efforts, polio remains endemic in Afghanistan and Pakistan, and in 2022 it showed a resurgence in Malawi and Mozambique. The new African cases were traced back to Pakistan.  

It just takes one 

When we look at polio in the developed world, it only takes one new infection to call public health and safety into question. 

In July 2022, in the first case of polio confirmed in the U.S. in 43 years, an unvaccinated young adult in Rockland County, New York, developed paralysis from the disease. This person seems to have been infected by an international traveler. The Centers for Disease Control and Prevention sent an investigative team, and researchers found multiple samples of the polio virus in wastewater—dating back to May—in the immediate region, as well as in New York City. By mid-August, no new cases had been reported, although experts say that the evidence gathered so far points to potentially hundreds more. 

Rockland County’s unusually low vaccination rates make this even more of a problem than it otherwise would be. The national rate of polio vaccination is about 93 percent, with the CDC considering four doses of the vaccine required for adequate immunization. In Rockland County, though, only slightly more than 60 percent of children below age 2 had received at least three doses as of August 2022. In one part of the county, the polio vaccination rate was only 37.3 percent. 

Now, based on the data gathered by the CDC, officials believe there is a high likelihood of community transmission in Rockland County, with “ongoing risk for paralysis” in people who are unvaccinated. The particular strain in Rockland County does carry a lower risk of paralysis, at 1 in 1,900 cases, but this also means that there may be large numbers of infected but completely asymptomatic people. 

Health officials are now concerned that new “non-wild” polio variants have cropped up in under-resourced locations around the world recently. Over the past three years, these variants have paralyzed some 2,000 children. It’s important to note that these “non-wild” variants develop when a community lacks a sufficient threshold of herd immunity to polio. The safe oral polio vaccine, with its weakened live virus, builds up immunity in vaccinated individuals. But it also then circulates among the unvaccinated or under-immunized in communities with sub-optimum sanitary conditions or without safe drinking water.  

The polio type identified in the infected person in Rockland County was of this “non-wild” variety.  

Bring back awareness of vaccines’ life-saving work 

Think about the polio vaccine campaign that began in the 1950s and ‘60s. It received overwhelming public support. Experts say this was the case largely due to the strong respect for science prevalent among Americans of all backgrounds at that time.  

Unlike today, there were no social media disinformation factories working 24/7 to create unwarranted vaccine hesitancy, as has been the case with COVID-19. We can see some of this fallout in the fact that, despite requirements that children entering school be immunized against polio, the vaccination rate has decreased in some areas of New York State and other regions in the country. Some of that is likely attributable to non-access during COVID-19 shutdowns, but now it’s time to ramp up our public health campaigns. Not just about COVID-19, but about all the vaccines that have protected us and our families so well for generations. 

In its Rockland County report, the CDC team wrote that even a single case of paralytic polio in the U.S. constitutes a “public health emergency.”