Polio Recently Turned Up Again—Here’s How a Leading Infectious Disease Doctor Says You Can Help Prevent It

Top infectious disease doctors explain why a disease the United States stamped out in the 1970s has suddenly resurfaced—and what you can do to help prevent it.

In September 2022, the Centers for Disease Control and Prevention (CDC) announced that the US had recorded its first case of polio since 2013. Within weeks, the virus was detected in New York City wastewater—a warning sign that the highly contagious disease may once again be circulating.

What’s the effect of polio? Polio is a virus that the CDC says “spreads from person to person and can infect a person’s spinal cord, causing paralysis” to parts of the body. Polio can start with flu-like symptoms and then in some cases develop into “more serious symptoms that affect the brain and spinal cord,” like paralysis and meningitis, the CDC explains.

Large outbreaks of polio were seen in the United States up until the 1950s, says Ashley Lipps, MD, an infectious diseases physician at Ohio State University’s Wexler Medical Center. In that era, the virus’s transmission caused an average of more than 15,000 cases of paralysis each year. “The first vaccine for polio was developed in 1955,” Dr. Lipps says, “and after that, rates of polio decreased dramatically.” In fact, the last case of polio originating in the US was in 1979.

To shed light on what’s suddenly happening with polio in 2022, The Healthy @Reader’s Digest spoke with top infectious disease doctors about why a disease the US stamped out in the 1970s has suddenly reemerged—and what you can do to prevent it.

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What is polio?

Polio is an intestinal virus, explains William Schaffner, MD, the Medical Director of the National Foundation for Infectious Diseases and professor of infectious diseases at Vanderbilt University Medical Center. One of the world’s leading infectious disease experts, Dr. Schaffner says that in spite of all of our hygienic measures, intestinal viruses tend to spread very easily from person to person—and the CDC says polio transmission rates are at nearly 100% for children and greater than 90% among adults.

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“[Polio] can cause some intestinal distress,” Dr. Schaffner says. “And if that’s all it did, we wouldn’t worry about it very much.” But about one in every 200 people infected develops irreversible paralysis, according to the World Health Organization.

“We don’t know why this happens, but the virus will leave the intestine and get into the bloodstream,” Dr. Schaffner explains. From there, it can make its way to your spinal cord, where it destroys the motor cells that send signals to muscles around your body. “It’s that paralytic polio that we’re trying to prevent.”

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Is polio reemerging in the US?

Since 1979, sporadic cases of polio have been recorded in the US—mainly in travelers who contracted the disease elsewhere, Dr. Lipps explains. And that’s what experts believe happened in New York this summer. “It appears they contracted [polio] from contact with someone from another country who received a live oral polio vaccine.”

This oral polio vaccine is a live, tamed version of the virus that offers immunity against the disease. But of every 3 million-or-so doses administered, a mutation can occur. This can cause paralytic disease. “Somewhere between six and 12 vaccine-associated cases of polio would occur each year [in the US],” he says, “and that became untenable.”

In the year 2000, the US switched from this oral vaccine to an inactivated version of the virus administered by syringe—and with no risk of this paralysis whatsoever. “In doing so, we eliminated polio in the United States.” But because it’s cheaper and easier to administer, the oral vaccine is still used in other parts of the world.

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So, what happened in New York? “There are some populations, clusters of people in the US, who are not vaccinating their children [against polio],” Dr. Schaffner says. In this August 2022 case, it’s likely that someone from an unvaccinated population traveled to another part of the world, coming into contact with someone who had taken the oral vaccine. And that tamed virus made its way into their intestinal tract. “Then they passed it to other people in their unvaccinated community—and at some point, the vaccine virus mutated in one young man, causing a case of paralytic disease.”

Fortunately, only one case of paralytic disease has emerged so far. “But it’s in the intestinal tracts of a lot of people.” That’s why public health officials are urging that everyone, especially in the New York area, get their polio vaccination status up to date.

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Should we be worried about a polio outbreak?

“Although this [case] is very concerning, those who are fully vaccinated against polio have little to no risk of contracting the disease,” Dr. Lipps says. “The polio vaccine is highly effective (more than 99%) at preventing polio.”

The polio vaccine series is typically given as a four-dose series—at age two months, four months, between six and 18 months, and between four and six years old—as a part of the standard childhood vaccination schedule. “For most people, no boosters are needed,” she says, however: “A booster is sometimes recommended for people at increased risk of exposure to polio, such as those traveling to countries where polio is endemic or where there are active outbreaks.”

If you’re unsure of your vaccination status, Dr. Schaffner says that the polio vaccine is widely available: “During Covid, many of us—children and adults—didn’t see our doctors or other health care providers as frequently.” So it’s as good a time as ever to check in with your doctor and make sure your vaccines are up-to-date.

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If your polio vaccine is taken care of, another meaningful way to fight the virus may be this: for every dollar that the U.S. service organization, Rotary International, commits to polio eradication, the Bill & Melinda Gates Foundation has committed two dollars. A representative for the Rotary and its 1.4 million volunteers in more than 200 countries tells us these philanthropies have partnered to donate more than $2.6 billion dollars, plus thousands of volunteer hours, and have immunized nearly three billion children in 122 countries against polio since 1985. Visit https://www.endpolio.org/donate to make your own pledge against polio.

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Leslie Finlay
In addition to The Healthy, Leslie has written for outlets such as WebMd.com, Fodors.com, LiveFit.com, and more, specializing in content related to healthcare, nutrition, mental health and wellness, and environmental conservation and sustainability. She holds a master's degree in Public Policy focused on the intersection between public health and environmental conservation, and an undergraduate degree in journalism. Leslie is based in Thailand, where she is a marine conservation and scuba diving instructor. In her spare time you'll find her up in the air on the flying trapeze or underwater, diving coral reefs.