Friday, September 16, 2022 (Kaiser News) – Before polio vaccines became available in the 1950s, people fearful of the disabling disease were afraid to let their children outside, let alone go to school. As polio reemerges decades after it was thought to be eradicated in the US, Americans unfamiliar with the dreaded disease need some guidance on how to protect themselves and their young children – many of whom have experienced the trauma of Covid-19 – Pandemic behind.
What is poliomyelitis?
Polio is short for “poliomyelitis,” a neurological disease caused by poliovirus infection. Of the three types of wild poliovirus—serotypes 1, 2, and 3—serotype 1 is the most virulent and most likely to cause paralysis.
Most people who are infected with the poliovirus do not get sick and have no symptoms. About a quarter of those infected may experience mild symptoms such as fatigue, fever, headache, stiff neck, sore throat, nausea, vomiting and abdominal pain. As with Covid-19, people who do not have symptoms can unknowingly spread it when interacting with others. But in up to 1 in 200 people with poliovirus infection, the virus can attack the spinal cord and brain. If it infects the spinal cord, people can develop muscle weakness or paralysis, including in the leg, arm, or chest wall. The poliovirus can also infect the brain, causing difficulty breathing or swallowing.
People can develop post-polio syndrome decades after infection. Symptoms can include muscle pain, weakness, and wasting.
People with poliomyelitis may remain wheelchair bound or unable to breathe without the help of a ventilator for the rest of their lives.
How is polio spread?
The virus that causes polio is spread by the “oral-faecal route,” meaning it enters the body through the mouth through hands, water, food, or other items contaminated with poliovirus-containing feces reached. In rare cases, the poliovirus 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 exams, laboratory tests, and scans of the spinal cord or brain. Healthcare providers may send in feces, throat swabs, spinal fluid, and other samples for laboratory testing. However, because polio has been vanishingly rare in the United States for decades, doctors may not consider the diagnosis for those with symptoms. And tests for suspected polio must be sent to the Centers for Disease Control and Prevention because even academic centers are no longer doing the testing.
How can transmission of the poliovirus be prevented?
The CDC recommends that all children 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 attending daycare or public school to be vaccinated against polio, but some states allow medical, religious, or personal exemptions. The Vaccines for Children program provides free polio vaccination to children who are eligible for Medicaid, are uninsured or underinsured, or are Native American or Alaskan Indians. Most people born in the United States after 1955 were probably vaccinated against polio. But in some areas, immunization 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 vaccines: killed inactivated polio vaccine (IPV) and attenuated live oral polio vaccine (OPV). IPV is an injectable vaccine. OPV can be given by drops in the mouth or on top of a sugar cube, making it 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-type poliovirus and live, attenuated OPV viruses can cause infection. Because IPV is a killed virus vaccine, it cannot infect or replicate, produce vaccine-derived poliovirus, or cause paralytic poliomyelitis disease. The weakened OPV viruses can mutate and regain their ability to cause paralysis — known as vaccine-associated poliomyelitis.
Since 2000, only IPV has been given in the United States. Two doses of IPV are at least 90% and three doses of IPV at least 99% effective in preventing paralytic poliomyelitis. The United States stopped using OPV because of a 1 in 2,000 risk of paralysis in unvaccinated individuals who received OPV. Some countries still use OPV.
Vaccination against polio began in the United States in 1955. Cases of paralytic poliomyelitis disease fell from over 15,000 per year in the early 1950s to under 100 in the 1960s and then under 10 in the 1970s. Today, poliovirus 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 as of 1994, but in June 2022 a young adult living in Rockland County, New York was diagnosed with vaccine-derived 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 contracted the infection in the United States. The CDC has since begun monitoring wastewater for poliovirus. Poliovirus, which is genetically linked to the Rockland County case, has been detected in sewage samples from Rockland, Orange and Sullivan counties, showing community spread as early as May 2022. An unrelated vaccine-derived poliovirus has also been detected in New York City sewage.
How do I know if I’m 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 records dating back to the 1990s. Your state or local health department may also have a record of your vaccinations. Individuals vaccinated 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 have been able to do this using the Docket app.
You can also ask your parents, your pediatrician, your current doctor or pharmacist, or the K-12 schools, colleges, or universities you attended if they have records of your vaccinations. Some employers, such as health systems, may also keep records of your vaccinations at their workplace health department.
There is no test to determine if you are immune to polio.
Do I need a polio booster shot if I was fully vaccinated against polio as a child?
All children and unvaccinated adults should get the CDC-recommended four-dose series of polio shots. You don’t need an IPV booster if you received OPV.
Adults who are immunocompromised, are traveling to a country where poliovirus is circulating, or are at increased risk of exposure to poliovirus at work, such as Some laboratory workers and healthcare workers, for example, may receive a one-time IPV refresher.
How is polio treated?
People with mild poliovirus infection do not need treatment. Symptoms usually go away on their own within a few days.
Paralytic poliomyelitis is not curable. Treatment focuses on physical and occupational therapy to help patients adjust and regain function.
Why hasn’t the polio virus been eradicated?
Smallpox is the only human virus that has been declared eradicated. A disease can be eradicated when it infects only humans, when viral infection induces long-term immunity against reinfection, and when an effective vaccine or other preventative exists. The more contagious a virus is, the more difficult it is to eradicate. Viruses that spread asymptomatically are also more difficult to eradicate.
In 1988, the World Health Assembly resolved to eradicate polio by the year 2000. Violent conflict, the spread of conspiracy theories, vaccine hesitancy, insufficient funding and political will, and inadequate immunization efforts slowed progress towards eradication, but prior to the Covid pandemic, the world was very close to eradicating polio. During the pandemic, childhood immunizations, including polio shots, declined in the United States and around the world.
To eradicate polio, the world must eradicate all wild poliovirus and vaccine-derived poliovirus. 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 involving the use of OPV, then a combination of OPV and IPV, and then IPV alone would likely be required to finally eradicate polio from the planet.
KHN (Kaiser Health News) is a national newsroom that produces in-depth journalism on health issues. Along with Policy Analysis and Polling, KHN is one of the three major operational programs of the KFF (Kaiser Family Foundation). KFF is a donated non-profit organization that provides information on health issues to the nation.