With Polio’s Return, Here’s What Back-to-Schoolers Need to Know

Don't listen to the anti-vaxxers! Your kids need their shots

Céline Gounder 

Before polio vaccines became available in the 1950s, people wary of the disabling disease were afraid to allow their children outside, let alone go to school. As polio appears again decades after it was considered eliminated in the U.S., Americans unfamiliar with the dreaded disease need a primer on protecting themselves and their young children — many of whom are emerging from the trauma of the covid-19 pandemic.

What is poliomyelitis?

Polio is short for “poliomyelitis,” a neurological disease 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 to cause paralysis.

Most people infected with poliovirus don’t get sick and won’t have symptoms. About a quarter of those infected might experience mild symptoms like fatigue, fever, headache, neck stiffness, sore throat, nausea, vomiting, and abdominal pain. So, as with covid-19, people who don’t have symptoms can unknowingly spread it as they interact with others. 

But in up to 1 in 200 people with a poliovirus infection, the virus may attack the spinal cord and brain. When it infects the spinal cord, people may develop muscle weakness or paralysis, including of the legs, arm, or chest wall. Poliovirus may also infect the brain, leading to difficulty breathing or swallowing.

People can develop post-polio syndrome decades after infection. Symptoms may 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 does polio spread?

The virus that causes polio spreads through the “oral-fecal route,” which means it enters the body through the mouth by way of the hands, water, food, or other items contaminated with poliovirus-containing feces. Rarely, poliovirus may spread through saliva and upper respiratory droplets. The virus then infects the throat and gastrointestinal tract, spreads to the blood, and invades the nervous system.