With the return of polio, here’s what back-to-schoolers need to know

Before polio vaccines became available in the 1950s, people wary of the debilitating disease were afraid to let their children go outside, let alone go to school. With polio resurfacing decades after it was deemed eradicated in the U.S., Americans unfamiliar with the dreaded disease need a primer to protect themselves and their young children — many of whom have suffered the trauma of the Covid-19 pandemic. overcome.

What is Poliomyelitis?

Polio is short for “poliomyelitis,” a neurological condition caused by a poliovirus infection. Of the three types of wild poliovirus – serotypes 1, 2 and 3 – serotype 1 is the most virulent and the most likely cause of paralysis.

Most people infected with polio virus do not get sick and will have no symptoms. About a quarter of those infected may experience mild symptoms such as fatigue, fever, headache, neck stiffness, sore throat, nausea, vomiting and abdominal pain. So, just like with covid-19, people who don’t have symptoms can unknowingly spread it while interacting with others. But in up to 1 in 200 people with a poliovirus infection, the virus can attack the spinal cord and brain. When it infects the spinal cord, people can develop muscle weakness or paralysis, including of the legs, arm, or chest wall. Poliovirus can also infect the brain, leading to difficulty breathing or swallowing.

People can develop post-polio syndrome decades after infection. Symptoms may include muscle aches, weakness, and wasting.

People with poliomyelitis may remain wheelchair-bound or unable to breathe for the rest of their lives without the help of a ventilator.

How does polio spread?

The virus that causes polio spreads through the “oral-fecal route,” meaning it enters the body through the mouth through the hands, water, food, or other items contaminated with feces containing polio virus. In rare cases, polio virus can spread through saliva and droplets from the upper respiratory tract. The virus then infects the throat and gastrointestinal tract, spreads to the blood and invades the nervous system.

How do doctors diagnose polio?

Poliomyelitis is diagnosed through a combination of patient interviews, physical exam, lab tests, and spinal cord or brain scans. Healthcare providers can send feces, throat swabs, spinal fluid, and other samples for lab testing. But because polio has been rare in the United States for decades, doctors may not consider the diagnosis for patients with symptoms. And tests for suspected polio should be sent to the Centers for Disease Control and Prevention, as even academic centers no longer run the tests.

How can polio virus transmission be prevented?

The CDC recommends that all children, ages 2 months, 4 months, 6 to 18 months, and 4 to 6 years of age, be vaccinated against polio, for a total of four doses. All 50 states and the District of Columbia require children who attend daycare or public school to be vaccinated against polio, but some states allow medical, religious, or personal waivers. The Vaccines for Children program provides free polio vaccines to children who are Medicaid eligible, uninsured or underinsured, or who are American Indian or Alaska Native. Most people born in the United States after 1955 have probably been vaccinated against polio. But in some areas, vaccination rates are dangerously low, like New York’s Rockland County, where it’s 60%, and Yates County, where it’s 54%, because so many families there claim religious exemptions.

There are two types of polio vaccine: killed, inactivated polio vaccine (IPV) and attenuated, live, oral polio vaccine (OPV). IPV is an injectable vaccine. OPV can be administered by drops in the mouth or on a sugar cube, so it is easier to administer. Both vaccines are highly effective against paralytic poliomyelitis, but OPV appears to be more effective in preventing infection and transmission.

Both wild polio virus and live attenuated OPV viruses can cause infection. Because IPV is a killed virus vaccine, it cannot infect or replicate, give rise to vaccine-derived poliovirus, or cause paralytic poliomyelitis. The attenuated OPV viruses can mutate and regain their ability to cause paralysis – what is called vaccine-derived poliomyelitis.

Since 2000, only IPV has been given in the United States. Two doses of IPV are at least 90% effective and three doses of IPV are at least 99% effective in preventing paralytic poliomyelitis. The United States stopped using OPV because of a 1 in 2,000 risk of paralysis among unvaccinated individuals who received OPV. Some countries still use OPV.

Vaccination against polio began in 1955 in the United States. Cases of paralytic poliomyelitis dropped from more than 15,000 per year in the early 1950s to less than 100 in the 1960s and then to less than 10 in the 1970s. Today, polio virus is most likely to spread where hygiene and sanitation are poor and vaccination rates are low.

Why is polio spreading again?

The World Health Organization declared the Americas polio-free in 1994, but in June 2022, a young adult living in Rockland County, New York, was diagnosed with poliovirus serotype 2. The patient complained of fever, neck stiffness and leg weakness. The patient had not recently traveled outside the country and was believed to have been infected in the United States. The CDC has since started checking wastewater for polio virus. Poliovirus genetically linked to the Rockland County case has been detected in wastewater samples from Rockland, Orange and Sullivan counties, indicating spread in the community as early as May 2022. Unrelated vaccine-derived poliovirus has also been detected in wastewater from New York City.

How do I know if I have been vaccinated against polio?

There is no national database of immunization records, but all 50 states and the District of Columbia have immunization information systems with data dating back to the 1990s. Your state or territorial health department may also have records of your vaccinations. People immunized in Arizona, the District of Columbia, Louisiana, Maryland, Mississippi, North Dakota, and Washington can access their immunization records using the MyIR Mobile app, and those vaccinated in Idaho, Minnesota, New Jersey, and Utah can do this using the Docket app.

You can also ask your parents, your childhood pediatrician, your current doctor or pharmacist, or the K-12 schools, colleges, or universities you attended if they have registered your vaccinations. Some employers, such as health care systems, may also keep your vaccinations in their occupational health center.

There is no test to determine if you are immune to polio.

Do I need a booster vaccination against polio if I was fully vaccinated against polio as a child?

All children and unvaccinated adults must complete the CDC’s recommended four-dose series of polio vaccinations. You do not need an IPV booster if you have received OPV.

Adults who are immunocompromised, travel to a country where polio virus is circulating, or are at increased risk of exposure to polio virus at work, such as some lab and health professionals, can receive a one-time IPV booster.

How is polio treated?

People with a mild poliovirus infection do not need treatment. Symptoms usually go away on their own within a few days.

There is no cure for paralytic poliomyelitis. Treatment focuses on physical and occupational therapy to help patients adapt and regain function.

Why has the polio virus not been eradicated?

Smallpox is the only human virus to be declared eradicated to date. A disease can be eradicated if it only infects humans, if viral infection induces long-lasting immunity against reinfection, and if there is an effective vaccine or other preventive agent. The more contagious a virus, the harder it is to eradicate. Viruses that spread asymptomatically are also more difficult to eradicate.

In 1988, the World Health Assembly decided to eradicate polio by 2000. Violent conflict, the spread of conspiracy theories, skepticism about vaccines, inadequate funding and political will, and poor quality vaccination efforts slowed progress toward eradication, but before the Covid pandemic, the world was very close to eradication. polio came. During the pandemic, childhood vaccinations, including polio vaccinations, declined in the US and around the world.

To eradicate polio, the world must eradicate all wild polioviruses and vaccine-derived polioviruses. Wild poliovirus serotypes 2 and 3 have been eradicated. Wild poliovirus serotype 1, the most virulent form, remains endemic only in Pakistan and Afghanistan, but vaccine-derived polioviruses continue to circulate in some countries in Africa and other parts of the world. A phased approach using OPV, then a combination of OPV and IPV, then IPV alone, would likely be necessary to eventually eradicate polio from the planet.


KHN (Kaiser Health News) is a national editorial that produces in-depth journalism on health issues. Together with Policy Analysis and Polling, KHN is one of the three major operational programs of KFF (Kaiser Family Foundation). KFF is an endowed non-profit organization that provides information on health issues to the nation.

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