World Polio Day 2024

October 24 is a big day for global health and international cooperation. It’s the birthday of the United Nations, which was founded 79 years ago today, and commemorated by the international community as UN Day. It’s also the birthday of Jonas Salk, who created the first successful vaccine against polio that set in motion decades of progress toward finally eradicating the disease. 

Today, on World Polio Day, we take stock of the progress we’ve made since Salk’s achievement—including 30 years since the Americas were declared free of wild polio—and look at the final hurdles to a polio-free world. 

Polio is an infectious and potentially life-threatening disease caused by the poliovirus. It mainly affects the nervous system and can cause muscle weakness, trouble breathing, paralysis, and even death. 

Before 1955, when Salk’s team at the University of Pittsburgh created the first polio vaccine, major polio outbreaks were a regular occurrence. Just three years before Salk’s discovery, the worst U.S. polio outbreak on record killed more than 3,000 children and left more than 20,000 paralyzed. 

The announcement of a successful polio vaccine made headlines around the world and rapidly transformed the fight against polio in the United States. A national vaccination campaign was quickly underway, with teens and children nationwide lining up to get their shots. By 1961, there were less than 200 polio cases in the U.S., down from 58,000 per year in the early 1950s. In 1979, the country was finally declared free of wild polio. 

Polio immunization, and progress towards global eradication, was initially slower but has been no less impactful. 

The creation of the first oral polio vaccine by Albert Sabin in 1962 was another key step in accelerating progress toward eradication. The ease of administering the oral vaccine made it well-suited for mass vaccination campaigns and—unlike the first polio vaccine—interrupted transmission of the virus in addition to protecting the child. Armed with these powerful new tools, countries were able to take up the fight against polio, at first through national immunization programs and then cooperatively through the World Health Organization’s Expanded Program on Immunization in 1974. 

Polio eradication truly took off in the 1980s, first with Rotary International’s historic commitment to ending the disease, then with the foundation of the Global Polio Eradication Initiative in 1988. During this same period, the member states of the Pan-American Health Organization (PAHO) unanimously resolved to end the endemic transmission of wild poliovirus in the Americas by 1990.

PAHO, working closely with UNICEF, Rotary, USAID, national governments, and others, spearheaded a strategy to vaccinate children on a massive scale. By holding national immunization days with the support of international partners, countries with weaker routine health systems were able to reach every child under five with polio vaccines. Eradication efforts also critically relied on strengthening laboratory capacity and disease surveillance to detect the virus before it could cause an outbreak. This combination of large-scale immunization and monitoring has remained a central pillar of immunization strategies.

The PAHO-led eradication effort was ultimately a success, demonstrating the power of international cooperation and setting the blueprint for eradication in future regions. In 1991, one year behind schedule, the Americas saw the last case of paralytic polio in the region. In 1994, the region was officially certified as wild polio-free.

Since then, the WHO’s Western Pacific (2000), European (2002), Southeast Asian (2014), and African (2020) regions have all been certified polio-free.

Today, wild poliovirus is endemic only in Afghanistan and Pakistan, and there have been fewer than 100 cases in 2024. But there are real hurdles to finally ending the disease. 

In Afghanistan, the Taliban government has severely limited women’s freedoms, with disruptions to often women-led polio campaigns just one of the far-reaching consequences. 

Outside of the endemic regions, there is still a risk of resurgence if immunization rates fall and surveillance is disrupted. The detection of the virus in Gaza and Sudan, where health systems have been devastated and millions have been displaced, is a grim reminder of how fragile this progress can be. Emergency vaccination campaigns to protect children and prevent major outbreaks are underway, but humanitarian pauses in the fighting must be respected for them to succeed. 

These enduring challenges should not overshadow all we have already achieved through polio eradication efforts. Wild polio cases are down 99.9% since the 1980s, and two of the three strains of the virus have been eliminated. The scale of the effort needed to maintain this progress in the face of a deadly, infectious disease is considerable. Finally ending polio will also require tremendous effort on the part of scientists, vaccinators, and families, but we know we can do it.

We have already come this far.