The first case of polio in over a decade was confirmed in Rockland County, New York, last week, according to the Deseret News.

An epidemiologist and infectious disease expert said that this case was traced back to travel.

“This young adult did not report recent travel outside the U.S. so was somehow exposed to another person’s live oral vaccine from outside the U.S.,” Dr. Monica Gandhi told Medical News Today.

What is polio?

According to the Center for Disease Control and Prevention, “Polio, or poliomyelitis, is a disabling and life-threatening disease caused by the poliovirus,” spreading through person to person contact. It can infect the spinal cord, causing paralysis, and lives in the throat and intestines.”

In the late 40s, this disease disabled 35,00 Americans every year, per Reuters. After the vaccine was introduced in 1955, the impact polio had on humans diminished, with cases rarely emerging.

How do polio vaccines work?

There are two types of vaccines that can prevent polio, per the CDC — the inactivated poliovirus vaccine, given as an injection, and the oral polio vaccine. The U.S. is the only country in the world to use the injection while the rest of the world adopted the oral form.

“We give (an) inactivated polio vaccine (IPV) in the U.S., but many countries use oral polio vaccine(s) as the live vaccine can spread to others and help protect a larger community. The oral polio vaccine is disabled (though live and capable of replication) and can occasionally revert to a form that can cause disease,” explained Gandhi.

In the case of the injected vaccine, two doses are 90% effective against Polio while three doses are 99% to 100% effective, the health agency stated.

Are polio vaccines still required in the U.S.?

There is no federal law requiring individuals to get polio vaccines but all 50 states and the District of Columbia mandate it.

How long is the vaccine effective?

Experts predict that the immunity can last many years after the initial series of doses, but exactly how long the vaccinated people can stay immune is unknown, per the CDC.

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“Most people do not need a polio booster because they were vaccinated against polio when they were very young,” said Dr. William Schaffner, an infectious disease specialist and professor at the Vanderbilt University School of Medicine, per Prevention.

“In general, there is no polio in the U.S. and no polio in most of the world, so people don’t need a booster.”


More than 7 in 10 people who get polio don’t have any visible symptoms, while 1 in 4 experience something similar to the flu, lasting two to five days.

The top symptoms include:

  • Sore throat.
  • Fever.
  • Tiredness.
  • Nausea.
  • Headache.
  • Stomach pain.
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