Polio Is In The News…Again

"Federal health officials are warning tourists from…across the country that global travel carries an increased risk for polio, which is circulating in about 30 countries.”

Dylan Siwicki, journalist, Patch

“As we can see from the detections in early 2026, polio remains just a plane ride away."

Karen McClorey-Hackett, www.vax-before-travel.com

A year ago, I thought we were getting close to eradicating poliomyelitis (polio). (“Eradication of Polio—A Stone’s Throw Away,” Germ Gems, March 12, 2025). I was overly optimistic.

This crippling neurologic viral infection remains endemic in Pakistan and Afghanistan. It also continues to plague many African countries. And while there have been no confirmed human cases of polio reported in Europe to date, active circulation of the virus was detected recently in wastewater in the United Kingdom (UK), Germany, Spain, and Finland. The virus therefore now poses a threat to unvaccinated travelers not only to Africa but also to some European countries. (Chen, E., “CDC warns travelers of polio before trips to Spain, UK and more,” USA Today, March 5, 2026). In this week’s Germ Gems post, I explain the basis for the tenacity of this viral infection and why it’s still in the news.

What is poliomyelitis (a recap)? In 1908, the Austrian physicians Karl Landsteiner and Edwin Popper discovered the poliovirus (PV), a highly contagious RNA enterovirus that causes the disease poliomyelitis. PV is acquired most commonly by consuming food or water contaminated by human feces. The virus enters through the mouth, replicates in the intestine and then can spread to the brainstem and the spinal cord causing neurologic symptoms. (Berg, S., “What doctors wish patients knew about polio,” American Medical Association, January 23, 2026).

About 75% of people infected with PV have no symptoms but can still spread the virus. About 25% of infected people, however, experience flu-like illness—fever, sore throat, headache, fatigue, and abdominal pain. In rare instances (less than 1%), the virus invades the bloodstream and from there the nervous system causing muscle weakness or irreversible paralysis, which can be fatal. Years after recovery from acute infection, some people develop a condition called post-polio syndrome with new symptoms such as slowly progressive muscle weakness, fatigue, and pain.

There is no cure for polio; the only treatment is supportive care. If respiratory muscles are affected, support with a mechanical ventilator may be necessary. (In 1952 when polio was at its peak in the U.S., the lives of thousands of polio victims were sustained by mechanical respirators aka “iron lungs.”). The best prevention against polio is not to get it in the first place.

Vaccines prevent polio. There are three PV serotypes each of which is referred to as a “wild type virus” and designated respectively as WPV1, WPV2 and WPV2. Due to extensive vaccination campaigns, WPV2 and WPV3 were eradicated in 2015 leaving only WPV1 which is endemic in Pakistan and Afghanistan.

In 1955, Jonas Salk developed an inactivated polio vaccine (IPV). Albert Sabin followed in 1960 with the development of an oral polio vaccine (OPV). Both vaccines are highly effective. The OPV is easier to administer than IPV (orally vs injection), can be distributed on a large scale and has a unique ability to stop person-to-person spread of PV. (www.polioeradication.org). While extremely rare (1 in 2.7 million doses), OPV can cause vaccine-associated paralytic polio (VAPP) if the attenuated virus in the vaccine reverts to a virulent form. This is the main reason that IPV is the vaccine of choice in most countries of the world, including the United States. (For the past twenty plus years, IPV is the only polio vaccine that has been used in the U.S.)

The polio battle today. The polio vaccines work so well that the United States as well as other countries have been able to eliminate the disease. Compared with the ~350,000 polio cases per year in 1988, today there are only dozens of cases worldwide (a reduction of over 99.9%). Polio eradication is certainly within reach but the battle goes on.

We are now combating: WPV1, one of the wildtype serotypes of PV (endemic in Pakistan and Afghanistan) and circulating vaccine-derived poliovirus (cVDPV). The cVDPV is an especially challenging problem.

In 2025, there were ~225 cVDPV cases circulating in Africa and parts of Asia. But ongoing transmission has now been reported in northern Nigeria, Chad, Somalia, Ethiopia, and Yemen. To address this problem, the World Health Organization (WHO) recently approved newer, more genetically stable oral polio vaccines to reduce the risk of vaccine-derived outbreaks.

Why worry about polio in wastewater? Wastewater monitoring is an early detection tool that can help communities prepare for and take action to address increasing cases of infectious diseases. (www.cdc.gov). It can detect traces of infectious diseases circulating in a community even if people don’t have symptoms.

The Global Polio Eradication Initiative (GPEI) is actively monitoring poliovirus detections worldwide focusing on wastewater surveillance in non-endemic regions and on ongoing transmission in core reservoirs. (www.vax-before-travel.com/people/karen-mcclorey-hackett). According to the GPEI, unusual wastewater detections were found in the UK (cVDPV2 detected in an environmental sample collected during routine wastewater surveillance in January 2026) and in Germany (WPV1 detected in Hamburg’s wastewater in late 2025). Even though no human cases of paralysis have been reported in these areas to date, these detections serve as critical early warnings.

The polio vaccines are effective in preventing polio. On March 3, 2026, the Centers for Disease Control and Prevention (CDC) issued a level 2 travel advisory for these and other countries warning that the PV had been detected in multiple destinations within the past 12 months and warning U.S. travelers to ensure that their polio vaccinations were up to date. (The CDC’s level 2 polio travel advisory included over 30 countries.) 

Polio is still with us. The WHO classifies polio as a Public Health Emergency of International Concern and emphasizes that any PV anywhere poses a threat to children everywhere. Global risks maintain the need for vaccination.

Vaccination is the key to eradicating this virus. The CDC recommends that children get 4 doses of polio vaccine to protect them against severe polio disease, including paralysis. Nonetheless, in the U.S., only 92.5% of kindergartners are vaccinated.

Kirk Milhoan, chair of the Advisory Committee on Immunization Practices, said that the “vaccine advisers were reconsidering vaccines because the risks of illnesses such as polio had dropped.” (Schreiber, M., “Fears of polio resurgence as U.S. vaccine adviser questions need for childhood shots,” The Guardian, February 23, 2026). This infuriated Art Caplan, PhD, head of the Division of Medical Ethics at NYU Grossman School of Medicine.

Caplan was one of the last Americans to get polio in the Boston outbreak in the 1950s. He said, “If you could gather up all the kids I saw die or become really severely disabled from 50 years ago, they would want you arrested…It’s horrifying and the height of irresponsibility to leave the door open even a crack.”

The U.S. has stopped fully recommending several key vaccines. More and more families are choosing not to vaccinate. And Aaron Siri, who specializes in vaccine lawsuits and is one of Robert Kennedy Jr.’s lawyers, has petitioned the government to revoke its approval of the polio vaccine. As Caplan warned, “You are begging to have a recurrence of the disease.”

There is no cure for polio. Right now, we are teetering between eradicating polio from this planet or having a resurgence of the disease across the globe. The choice seems simple; get vaccinated to avoid the disease and to help protect others.