“According to the Global Polio Eradication Initiative, 85% of polio cases in 2024 were in fragile and conflict affected settings.”
Yousif Ali, et al., Sudan Field Epidemiology Program
“It’s pockets of the unimmunized that can bring diseases back.”
Patsy Stinchfield, former president of the National Foundation for Infectious Diseases
Smallpox is the only infectious disease that been eradicated. (Eradication is defined as “a permanent reduction to zero of the worldwide incidence of infection.”) And, we are just a stone’s throw away from also banishing polio, another cruel viral disease, to this historical dustbin. (See “Eradication of Polio: Stuck in the Red Zone,” Germ Gems, October 11, 2019.) Unfortunately, certain impediments, that is, human conflicts both military and political, stand in the way. In today’s post, I provide a brief summary of the key features of polio and discuss the obstacles impeding polio’s eradication.
What is polio? In 1908, the Austrian physicians Karl Landsteiner and Edwin Popper discovered the polio virus (PV) that causes the disease poliomyelitis (or polio). PV is a highly contagious RNA enterovirus that most commonly is acquired by consuming food or water contaminated by human feces.
Three out of every four people infected with PV are asymptomatic after infection. In rare instances (less than 1%), the virus invades the bloodstream and from there the nervous system causing a neurological disorder called paralytic polio.
There is no cure for this viral infection. The only treatment available for polio is supportive care. Those with neurologic sequelae may require help with ventilation of their lungs. (In 1959, 1,200 polio victims in America were using “iron lungs” to breathe, or were fitted with braces for their weakened limbs to walk.)
Polio vaccines prevent polio. The best way to fight polio is vaccination. In 1955, Jonas Salk developed an inactivated polio vaccine (IPV), and this was followed in 1960 by Albert Sabin’s development of an oral polio vaccine (OPV).
Both vaccines are highly effective, but the OPV can rarely cause vaccine-associated paralytic polio (VAPP) if the attenuated virus in the vaccine reverts to a virulent form. While this is extremely rare, it is the main reason IPV is the vaccine of choice in most countries of the world, including the United States.
Enter the Global Polio Eradication Initiative. In 1988, polio was present in more than 125 countries and paralyzed about 1,000 children per day. That same year, the Global Polio Eradication Initiative (GPEI), a public-private partnership aiming to eradicate polio worldwide, was launched involving the World Health Organization (WHO), Rotary International, the U.S. Centers for Disease Control and Prevention, UNICEF, the Bill and Melinda Gates Foundation, and Gavi, the Vaccine Alliance. Through their collaborative efforts, the incidence of polio has been reduced by over 99%.
PV strains currently battled by GPEI. The three PV serotypes are: type 1(PV1), type 2(PV2), and type 3 (PV3). Each of these three PV types is referred to as a “wild type virus,” designated respectively as WPV1, WPV2, and WPV3. Due to extensive vaccination campaigns, WPV2 and WPV3 were eradicated in 2015 leaving only WPV1, which is endemic only in Pakistan and Afghanistan. A number of circulating vaccine-derived polioviruses (cVDPVs), however, have emerged, especially in African countries and Indonesia. In 2024, 190 cVDPV cases were reported.
On February 25, 2025, the GPEI announced that Saudi Arabia had committed $500 million to end polio. This fund is intended to help vaccinate 370 million children annually to stop transmission of WPV1 in Pakistan and Afghanistan and outbreaks of cVDPV in African countries, as well as in conflict zones, such as Gaza, where the first case of polio in 25 years was reported last summer.
Role of human conflict in a possible polio resurgence. On February 19, 2025, the WHO announced that mass polo vaccination was to resume in Gaza. But, Gaza isn’t the only conflict zone with major challenges in the fight against polio. As was pointed out in an article in a recent issue of The Lancet,“in Ukraine, polio resurfaced for the first time since 2002,” and in Sudan, “58 polio cases were reported across 18 states in August, 2022,” according to the latest data from that country’s Ministry of Health. (See, “Polio in Sudan and other conflict zones: a call for urgent support,” The Lancet, January 25, 2025.)
Closer to home, it isn’t armed conflict that threatens the U.S. with potential resurgence of polio. Instead, it’s purveyors of misinformation/disinformation and antivaxx groups who willfully ignore the fact that the most effective way to fight polio is to prevent it by vaccination.
“Before 1955, when the vaccine was introduced, polio disabled more than 15,000 Americans each year and hundreds of thousands more worldwide. In 1952 alone, it killed 3,000 Americans after paralysis left them unable to breath.” (See, Apoovra Mandavalli, “How Lagging Vaccination Could Lead to a Polio Resurgence,” New York Times, January 13, 2025.) Once they were introduced, the polio vaccines almost immediately began reversing the course of the disease in the U.S. (See, Tara Haelle, “Polio Vaccines Saved America from Disease, What Happens if We Lose Them?,” National Infectious Diseases Foundation, January 30, 2025.)
The vaccines have been similarly effective in eliminating the disease from most countries, including the U.S. Nonetheless, Secretary of Health and Human Services Robert F. Kennedy, Jr. said that the “idea that vaccination has nearly eradicated polio is ‘a mythology.’” And, Kennedy’s lawyer “has petitioned the U.S. Food and Drug Administration to revoke approval of the vaccine used in the United States. (Brenda Goodman, CNN, December 13, 2024.)
Senate Majority Leader and polio survivor, Mitch McConnell was the only Senate Republican who opposed Kennedy’s heading the Department of Health and Human Services. McConnell was cleareyed and clearheaded about the extraordinary benefit of the polio vaccine when issuing this statement: “The polio vaccine has saved millions of lives and held out the promise of eradicating a terrible disease. Efforts to undermine public confidence in proven cures are not just uninformed—they’re dangerous.”
Highly immunized communities are the defense against polio. Currently, approximately 93% of U.S. children are vaccinated against polio by age two. Let’s hope that that remains the case. Then, as Walter Ornstein, former associate director of the Emory Vaccine Center at Emory University, said, “The offense is finishing the job of eradicating polio.”
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