Late last week, the polio virus was discovered to be quietly circulating in New York City wastewater. That discovery comes just weeks after a case of polio was confirmed in an unvaccinated 20-year-old in upstate New York, marking the first U.S. case of polio in a decade.

“The presence of polio in wastewater means it's circulating in the community, the level to which we don't yet know,” says Mona Amin, DO, FAAP, a pediatrician who practices in Florida. 

Until now, the community spread of polio had been considered eliminated in the U.S. since 1979, thanks to the success of widespread vaccination efforts. However, the virus has not been completely eradicated, as occasionally it enters the country via travelers from other locations where polio is still circulating. 

Related: What parents need to know about AFM—the polio-like illness affecting children

Most adults and kids have likely already been vaccinated against polio, but, thanks to the pandemic, larger numbers of kids are falling behind on their routine childhood vaccinations, meaning that some kids could be left unprotected. 

Because the polio virus can cause permanent paralysis and be especially severe for young children, Dr. Amin is urging parents to confirm that kids are up to date on the polio vaccine “as soon as possible”—whether you live in New York or not.

“It is highly advised to be up-to-date on vaccinations for those who are eligible,” Dr. Amin says, adding that she recommends checking both your and your child’s immunization records within the next week. “This will help protect those who are too young to be vaccinated or who are not yet fully vaccinated.” 

What to know about polio

Polio, short for poliomyelitis, is a highly contagious enterovirus (parechovirus is another type of enterovirus) that can be permanently disabling or deadly. Polio is transmitted through close contact, through contact with feces of infected people, and in some cases, can be transmitted through respiratory droplets, though that route is less likely than others. The virus can live in the throat or intestines of infected people for weeks

There is no cure or treatment for polio, but infection can be prevented through the highly effective polio vaccine.

But now’s not the time to panic, stresses Dr. Amin. “The risk right now is low and the best protection we have is vaccination,” she says. 

The chances of there being a huge outbreak of polio cases is unlikely, given that 92.6% of U.S. children had been fully vaccinated against polio in 2019. Thanks to widespread school mandates, the polio virus doesn't have many hosts available to infect. 

But in certain communities where vaccination rates are low, the risk of cases cropping up is more likely. In New York City, just 86% of children under 5 have received a full course of immunization. 

Polio symptoms

Polio infection does not present with symptoms in the majority of cases, but in some instances, it can lead to meningitis, which can result in permanent paralysis. 

While most people infected with polio will not have any symptoms, about 1 in 4 people may experience the following: 

  • Sore throat  
  • Fever
  • Fatigue 
  • Nausea
  • Stomach pain

In approximately 1 of 25 cases, polio can cause viral meningitis, and about 1 in 200 of those with meningitis will become paralyzed. 

Related: 9 facts parents need to know about parechovirus in newborns

What to know about the polio vaccine

The polio vaccine currently used in the U.S., the inactivated polio vaccine (IPV), has a strong safety record—and is highly effective. Two doses are at least 90% effective against paralytic polio, while three doses are at least 99% effective. A fourth dose, or booster, is recommended to confirm immunity lasts, says Dr. Amin.

For adults, three shots are recommended, and for kids, four shots are standard. As part of the routine childhood immunizations, the CDC recommends the following polio vaccine schedule

  • 2 months of age
  • 4 months of age
  • 6 through 18 months of age
  • 4 through 6 years of age

Any parent of a young child should also get vaccinated if they haven’t yet, in order to better protect their children. “For those too young to be vaccinated or for someone who has not yet gotten their 3 doses [think any child under 6 months], the best prevention is to surround them with people who are up-to-date on their vaccines,” notes Dr. Amin.

Related: CMV is a highly common cause of birth defects—but you've probably never heard of it

Do I need a polio booster?

If you were fully vaccinated as a child, you’re most likely to still be well protected today, as the immunization lasts for years. The CDC is currently investigating whether boosters may be necessary for some adults in New York who are considered more at risk. If you’re unsure if you were vaccinated as a child, talk to your doctor about whether you should start a new round of three doses. 

According to the CDC, people most at risk for polio infection are:

Some healthcare workers in New York may soon be eligible for a one-time polio booster. Be sure to check with your state’s health department. 

Related: Childhood vaccination rates continue to plummet since the start of the pandemic

Even if you don’t live in New York, polio vaccination is important

Experts are concerned that the virus’s detection in New York City wastewater means that cases could already be spreading silently, given that most cases don’t appear with symptoms.  

Even if you don’t live in New York, talk to your doctor and your child’s pediatrician to make sure you’re both up-to-date on your vaccines for polio and other viruses that can be potentially avoided with vaccine-provided immunity, like measles, hepatitis and chickenpox. 

Getting yourself and your family vaccinated can protect you personally from the risk of paralysis from polio, and it can also help stop the spread. 

“Immunization provides individual protection but community protection by breaking chains of transmission and keeping polio away,” says Walter Orenstein, an epidemiologist at Emory University, to Slate

Widespread vaccination virtually eliminated polio before, and those efforts can do it again. 

Featured expert

Mona Amin, DO, is a board-certified pediatrician based in Florida. Find her @pedsdoctalk and pedsdoctalk.com.