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Americans have a lot on their plates right now: the COVID pandemic, a monkeypox outbreak, and now polio, a serious and life-threatening disease that’s very contagious, has no treatment, and poses a low yet viable risk of paralysis in adults and children who get infected. Chaos has already erupted within family group chats, now littered with frantic messages to parents asking about polio vaccination records.
The latest public health threat got real when the New York health department in July confirmed the US’s first polio case in nearly a decade in an unvaccinated Rockland County resident, a finding bolstered by wastewater samples confirmed polio positive in the area as early as May.
The person experienced paralysis, which is typically permanent, but it’s unclear how their health status has improved or changed.
(Health officials are not revealing the person’s age or sex for privacy reasons. But an anonymous health official told the Washington Post that this person is a 20-year-old man who had traveled to Poland and Hungary this year and was hospitalized in June. The man is able to stand but is having difficulty walking, the Washington Post reported in July.)
The last wild polio case that originated in the US occurred in 1979. However, since then, a handful of infections have emerged in people who live in regions where the virus still spreads. (There’s been a worldwide effort to eradicate polio, similar to the way smallpox was wiped from the earth thanks to vaccines, but stubborn pockets of infection persist in two countries, Pakistan and Afghanistan.)
The virus has been detected in wastewater samples in Orange County, New York, and more recently in New York City as early as June, which “is alarming, but not surprising,” New York State Health Commissioner Dr. Mary Bassett said in a news release posted Aug. 12.
All of the wastewater samples collected so far (except the ones from NYC) have been “genetically linked” to the Rockland County case, suggesting polio is spreading locally among people with no or mild symptoms. Polio symptoms can include fatigue, nausea, headache, stomach pain, and sore throat, and it can be nearly impossible to distinguish from other illnesses. What’s more, the Rockland County case is genetically linked to polio wastewater samples collected in Israel and London, despite the person having no travel history to or from these regions.
Officials in New York (and London) are urging unvaccinated children and adults, including pregnant people, to get vaccinated against polio if they haven’t already, stating that “for every one case of paralytic polio observed, there may be hundreds of other people infected.”
Bassett said officials are treating this case “as just the tip of the iceberg of much greater potential spread.”
Although the majority of polio cases cause mild symptoms, a few people with polio go on to develop mild meningitis, an infection in the brain and spinal cord membranes. Even fewer will become paralyzed if the virus enters their spinal cord. It’s said that about one out of every 200 polio cases will result in paralysis.
But it’s a dangerous illness that caused 15,000 cases of paralysis each year before vaccines became available in the 1950s. (One Texas man has lived more than 70 years in an iron lung due to a polio infection at age 6.) The development of the polio vaccine was considered one of the most important scientific accomplishments of the 20th century.
Given the history, BuzzFeed News set out to discover how much of our already depleted energy should be spent on worrying about polio infection, and whether those of us who were vaccinated as kids should seek a booster.
While experts we spoke to expressed genuine concern about the unexpected and disturbing local transmission we’re seeing, they made one point clear: Vaccinated people should be fine; unvaccinated people are not.
“It’s a real wake-up call for everybody that this vaccine-preventable disease is out there. It’s been over 40 years since there was a case acquired in the US, and that’s what makes it scary,” said Dr. Dean Blumberg, chief of pediatric infectious diseases at the University of California, Davis. “There’s enough susceptibility because of vaccine hesitancy that it’s almost certain it’s going to spread and be detected in other communities.
“So I think everywhere, no matter where you are in the world, it’s important to be up to date with your vaccines in general, and specifically with the polio vaccine.”
How did the Rockland County resident get polio?
How the Rockland County resident contracted polio remains unclear, a spokesperson with the Rockland County Department of Health told BuzzFeed News. But we do know that this person did not travel out of the country within the period of infection based on when their symptoms emerged, the spokesperson said.
Genetic analyses show that the Rockland County resident’s infection was caused by “vaccine-derived poliovirus type 2,” or VDPV for short.
This is a mutated version of the weakened live polio virus that’s contained in the oral polio vaccine, or OPV, which is still given in other countries but has not been administered in the US since 2000. This weakened virus mutates into a different form that can cause illness — and paralysis — if allowed to spread in people who are not fully vaccinated, not vaccinated at all, or immunocompromised, in which the virus can be shed for longer periods of time.
All this means that the Rockland County resident likely contracted polio from another person in the US who was vaccinated with OPV in another country, but this has not been confirmed.
Poliovirus can live in your gut for several months, according to Blumberg, which isn’t great news considering the virus spreads primarily via the fecal–oral route. So touching a dirty diaper or public bathroom, or even eating food prepared by an infected person who didn’t wash their hands properly after using the restroom can expose you to polio.
The virus can last in the respiratory tract for about one to two weeks, Blumberg said, but airborne transmission isn’t how this virus spreads best.
In other words, the Rockland County resident could have contracted polio at any point while in public settings. Health officials do make clear, however, that this person is not necessarily the source of the ongoing local transmission in the New York area.
VDPVs can be responsible for polio outbreaks in regions where vaccination rates are low, like Rockland County, which has a polio vaccination rate of about 60%, meaning 60% of children have received three doses before their second birthday. Orange County, New York, where wastewater samples have turned up positive, has a polio vaccination rate of about 58%. These compare to the statewide average of about 79%.
Three cases of VDPVs have occurred in the US since 2000 prior to this event: one in 2005, another in 2008, and one fatal case in 2013, according to the CDC. All of these infections were related to mutated viruses from the OPV and happened in kids and adults who were not vaccinated or had a weakened immune system.
What’s the risk that vaccinated people get polio?
The only polio vaccine that has been administered in the US since 2000 is the inactivated polio vaccine, or IPV. The country began using this shot in 1987 but started using it exclusively in 2000 to get rid of the risk of VDPV from the oral vaccine.
IPV does not contain live poliovirus, so people cannot infect others once vaccinated. The only downside to IPV is that it cannot stop wild poliovirus from spreading (although this isn’t and hasn’t been a concern in the US for a while). This is because it offers lower levels of immunity inside our GI tract than the OPV.
It’s recommended that children receive a total of four doses of IPV, including at 2 months of age, 4 months, 6 through 18 months, and then the fourth dose between the ages of 4 and 6. Two doses of IPV are 90% protective against all wild polioviruses, as well as VDPVs. Three doses are 99% effective, the CDC says, adding that 99 out of 100 kids who get all recommended doses are protected.
Overall, vaccines protect us against infection. Breakthrough infections are very rare, but if they do occur, illnesses typically carry no or mild symptoms, the CDC says. Polio vaccines also protect against paralysis, even in people who do get a breakthrough infection.
Should you get a polio booster?
But what about us anxious adults? Should we get boosters to improve our protection as polio spreads? The short answer is no, according to Dr. Adam Ratner, director of pediatric infectious diseases at NYU Langone Health.
“People who are fully vaccinated, including adults who got their full series when they were kids, don’t have a lot to worry about right now in terms of your risk of getting paralytic polio, even if exposed to poliovirus,” Ratner said. “The most important thing is finding the people who are completely unimmunized and getting them their primary series.”
That said, if parents of young kids aren’t sure if their child received the polio vaccine or finished their series, it’s safe to give them a booster shot, according to Ratner. “It wouldn’t be dangerous to do that,” he said.
The only circumstances that warrant greater risks of polio infection are those that involve travel to a country where polio has not been eradicated, such as Afghanistan and Pakistan; work in a lab that involves handling polioviruses; and close contact with polio patients as a healthcare provider.
Adults in these groups who have been vaccinated can receive one lifetime booster of IPV. Those who have not been vaccinated should receive three doses. The first can happen at any time, followed by a second shot one to two months later, and the third six to 12 months after that.
Adults who have only had one or two doses should complete their vaccination series, experts suggest, no matter how long it’s been since their last dose.
“For people who are fully vaccinated, the risk of developing paralytic polio is not zero, but very close to zero,” Ratner said. “The people who should be worried are the people who either are not fully vaccinated or people who live with family who are not fully vaccinated against polio.”
How long does polio vaccine protection last?
We don’t know exactly how long protection from the IPV lasts, but the CDC says vaccinated people are “most likely protected for many years after a complete series.”
A 2021 study suggests that protection from OPV (which some older adults in the US may have received as a child) lasts for at least up to 18 years after vaccination, with some antibodies lasting for more than 30 years after a last dose.
A separate 2021 study published in the Journal of Infectious Diseases found some evidence that protection from IPV remained strong for at least 10 years post-vaccination.
