Polio in US: What we know and what the symptoms are

In the middle of the 1900s, American parents were concerned about letting their children to go to birthday parties, pools, or anywhere else they might gather as the fear of polio took hold of the US, with images showing children using wheelchairs reminding the nation of the perils of the illness.

The authorities closed down restaurants and other public spaces to prevent the spread of the disease, much like during the Covid-19 pandemic, according to Dr Rosemary Rochford, a professor of immunology and microbiology at the University of Colorado Anschutz School of Medicine.

Writing for The Conversation, Dr Rochford noted that in 1952, it was estimated that there were 58,000 polio cases and 3,145 deaths caused by polio in the country. Those figures started to drop quickly following the start of a vaccination campaign three years later.

Two decades later, in the 1970s, fewer than 10 cases of paralysis connected to polio were recorded in the US. In 1979, the virus was considered to have been eliminated in the US. Fear of the illness has since faded.

But in July of this year, it was reported that an unvaccinated New York man had caught the illness and developed paralysis. It was the first case in the country since 2013.

There’s no cure for the disease, meaning that the only way to protect yourself is to get vaccinated to prevent infection.

The virus is transferred between people via the mouth. Touching an object that has been contaminated, such as cutlery or a glass, can pass on the virus, as can drinking contaminated water.

An infected person releases the virus in their face, prompting worries following reports that the virus has been found in the wastewater in New York for several months.

New York Governor Kathy Hochul declared a state of emergency on Friday to increase rates of vaccination as it’s becoming clear that the virus is spreading in some areas.

New York State Health Commissioner Mary Basset said last month that the state department of health is “treating the single case of polio as just the tip of the iceberg of much greater potential spread.”

“Based on earlier polio outbreaks, New Yorkers should know that for every one case of paralytic polio observed, there may be hundreds of other people infected,” she said.

“On polio, we simply cannot roll the dice,” she added on Friday, according to a press release. “If you or your child are unvaccinated or not up to date with vaccinations, the risk of paralytic disease is real. I urge New Yorkers to not accept any risk at all. Polio immunization is safe and effective – protecting nearly all people against disease who receive the recommended doses. Do not wait to vaccinate. If you are unsure of you or your families’ vaccination status, contact a healthcare provider, clinic, or local county health department to make sure you and your loved ones receive all recommended doses.”

Many cases fly under the radar as people don’t show symptoms or the symptoms are similar to a case of the flu. But an infected person without symptoms can still spread the virus.

About 70 per cent of those infected develop no symptoms, while 25 per cent develop flu-like symptoms, CNBC reported.

Washing your hands is one of the primary ways of preventing the spread of the virus as it spreads via surfaces.

Several solutions used to disinfect items, including alcohol or diluted Lysol, don’t remove the virus, but chlorine bleach manages to destroy it. This prompted chlorine to be used in swimming pools.

Viruses that a person ingests are usually handled by stomach acids but the polio virus can survive this and make it to an individual’s gastrointestinal tract, where an infection can fester, according to Dr Rochford.

An average of about one out of 200 people infected develop paralysis and researchers have yet to discover what makes someone vulnerable.

Within the group of people who gets paralytic polio, the virus can affect lower motor neurons in the brain stem and spinal cord, which helps a person control their muscles, leading to paralysis. Legs are most usually affected but other body parts can also be inhibited.

The virus can also harm the nervous system that manages breathing.

Most immune systems can handle a bout of the infection, with researchers locating antibodies fighting the virus in those who recover, Dr Rochford notes.

Post-polio syndrome is when those who have survived paralytic polio experience fatigue and weakness in their muscles. Other symptoms can also be connected to the syndrome, such as problems sleeping, chronic pain, struggling with swallowing and handling the cold, as a result of lacking blood supply.

There’s no agreed-upon number on how many survivors of polio develop post-polio syndrome as it’s diagnosed based on symptoms. Estimates go from 15 to 80 per cent, according to Dr Rochford.

The Global Polio Eradication Initiative was launched in 1988, when 300,000 children in 125 countries suffered from the illness, according to the Centers for Disease Control and Prevention (CDC). Last year, six cases were registered.

Globally, vaccines come in two types. Since 2000, the type used in the US has been a shot that includes poliovirus that has been inactivated, which kills the virus and stops it from multiplying in the body.

US kids get the shots at the ages of two months, four months, and finally between six and 15 months. The series of shots provides people with protection set to last for the rest of their lives.

Large parts of the world use a vaccine, a weakened form of the virus, taken via the mouth.

The oral vaccine is used in areas where mouth-to-mouth transmission is a threat while the injection is more focused on preventing disease within a vaccinated individual.

If the number of vaccinated people decreases below a certain level, the virus can begin to lead to illness. Some areas of the world are below the threshold for community protection with the recent case in New York believed to have been brought from abroad.

Last year, 80 per cent of infants on a global level got three doses of vaccine battling polio, according to the World Health Organisation (WHO).

“Targeted for global eradication, polio has been stopped in all countries except for Afghanistan and Pakistan,” the WHO website states. “Until poliovirus transmission is interrupted in these countries, all countries remain at risk of importation of polio, especially vulnerable countries with weak public health and immunization services and travel or trade links to endemic countries.”

According to the CDC, around 93 per cent of children in kindergarten in the US had received four doses of the polio vaccine by the 2020-2021 school year.

Louisiana and Mississippi had the highest vaccination rates, at above 98 per cent, with the District of Columbia coming in last with around 80 per cent.