Polio: Then vs. Now

Recent cases of polio in the United States have caused some public health officials to sound the alarm and reiterate the importance of polio vaccines. Luther Rhodes, MD, infectious diseases physician with LVPG Infectious Diseases, outlines how a polio outbreak today could be different than it was 60 years ago.

Throughout the early part of the 20th century, polio, a debilitating and often deadly infectious disease, struck fear in the hearts of people throughout the world. The virus invades the central nervous system and can cause paralysis. At its peak, polio was responsible for paralyzing approximately 35,000 people a year, many of them children.

Thanks to vaccines, which were introduced in the early 1950s, polio was considered eradicated from the United States in 1979. There have only been three known cases since then in the United States, the last one diagnosed in 1993. However, a recent case in upstate New York has sparked concern from public health officials.

“I think that everyone really thought polio was gone, so it was surprising to find a case after so long. There are still pockets of people who are unvaccinated for various reasons. Therefore, it’s concerning to find any cases of polio,” Rhodes says.

The poliovirus found in New York is not the same virus that originally affected the world 60 years ago. Vaccinations have eliminated that strain in all but two countries. However, many polio cases now are actually from a type of the polio vaccine that is no longer used in the U.S.

There are two types of polio vaccines. An inactive version (IPV) is given via injection and uses an inactivated version of the virus. The other type is an oral polio vaccine (OPV) that uses a live, weakened form of the virus, given as a sugar cube.

According to Rhodes, the United States has used the IPV vaccine exclusively since 2000 because the oral vaccine was causing a small percentage of vaccine-derived polio. “The oral polio vaccine was very successful, but people who take the vaccine in that form can shed the virus, causing it to spread among those who are not vaccinated. It’s rare, only about one person in a million can transmit the paralytic virus, but it is possible,” Rhodes says.

Wastewater in the area in New York where the polio case was detected has tested positive for the virus. However, it’s thought that it’s most likely from vaccinated individuals infected with vaccine-derived virus, which means they have no symptoms and are at no risk for paralysis.

According to Rhodes, the most important thing you can do to protect yourself and your family is make sure everyone is vaccinated against polio.

“There is certainly no reason to panic about polio,” Rhodes says. “There are vaccines available to prevent the disease. Because polio can be devastating for children, it’s important to make sure they are vaccinated. Most children are required to have the vaccine in order to attend school, however, COVID has caused some delays in vaccinations. If you’re unsure whether your child is fully vaccinated, check with their doctor.”

The Centers for Disease Control and Prevention (CDC) recommends the inactivated polio vaccine (IPV) as part of the series of routine childhood vaccines.

Children get four doses of the vaccine. They get one dose at the following ages:

• 2 months
• 4 months
• 6 through 18 months
• 4 through 6 years

If you were vaccinated against polio as a child, there’s generally no reason to get the vaccine as an adult. However, if you are an unvaccinated adult or didn’t receive the complete polio vaccine series as a child, you may want to consider getting vaccinated. Some situations put you at a higher risk for polio, including:

• Traveling to another country with a greater risk for contracting polio
• Working in a lab and handling specimens of polio
• Treating patents infected with polio or those who have close contact with someone infected with polio