Well-Being Prevention & Cures

What to know about polio as it resurfaces

The virus is likely to be circulating, since many people are asymptomatic or have only flu-like symptoms.
box labelled inactivated polio vaccine
Getty Images

Story at a glance


  •  Polio is caused by a virus and spread through contact with feces.

  • The virus infects the throat and intestines, and can cause flu-like symptoms.

  • Paralysis from the polio virus is rare.

This year, polio cases have been detected in New York state, London and Jerusalem. Spread mostly through contact with an infected person’s feces, vaccination is protective against illness, paralysis and death from the polio virus. With schools back in session or shortly to begin, here’s what to know about polio. 

In July, the case in Rockland County in New York was in an otherwise healthy young adult who was unvaccinated but had a confirmed case of poliomyelitis resulting in paralysis in the leg. The county also found the virus in wastewater samples from June. 

Polio was also found in wastewater samples in New York city, suggesting that it is more widespread than a single case. “For every one case of paralytic polio identified, hundreds more may be undetected,” State Health Commissioner Mary T. Bassett said in a statement. “The detection of poliovirus in wastewater samples in New York City is alarming, but not surprising.” 

Most people who are infected will not have visible symptoms, according to the Centers for Disease Control and Prevention (CDC). One out of four people may have flu-like symptoms, like sore throat, fever and fatigue. An even smaller number of people may have neurological symptoms because the virus can travel into the spinal cord, including meningitis (infection of covering of spinal cord and/or brain) or paralysis. 

According to the CDC, the polio virus can spread through person to person contact, most commonly through contact with feces and less so through droplets from a sneeze or cough. It typically enters the body through the mouth and infects the throat and intestines. 

The current polio situation in New York state is being monitored closely. “The best way to keep adults and children polio-free is through safe and effective immunization – New Yorkers’ greatest protection against the worst outcomes of polio, including permanent paralysis and even death,” says Bassett in the statement. In New York City, there are some pockets where vaccination coverage is under 70 percent in children ages 6 months to 5 years old. 

map of new york city, color coded by percent coverage polio vaccinated, text on the left side showing breakdowns by borough, and by neighborhoods with highest and lowest percentages
Breakdown of polio vaccination coverage in New York city by boroughs and neighborhoods

In the United Kingdom, polio virus has been detected in the wastewater since February. Health experts are warning that the strain that is circulating is derived from an older, less used version of a vaccine that contains a weaker live virus. This virus from the vaccine can mutate and adapt if allowed to circulate in the population. The government in London is aiming to vaccinate all 1- to 9-year-old children. 

The polio vaccine is included in the standard childhood vaccination schedule. To find out if you’ve been vaccinated against polio, look for IPV, which stand for inactivated polio virus, on your immunization card. If you received your vaccine in some other countries, it might say OPV, which is the oral polio vaccine.