Poliomyelitis, commonly known as polio, was one of the most feared diseases of the 20th century. It struck indiscriminately, particularly targeting children and often resulting in paralysis or death. For years, scientists searched for a solution to this devastating illness. Two names, Dr. Jonas Salk and Dr. Albert Sabin, stand out for their pioneering contributions to the development of polio vaccines. Their work, though different in approach, played a crucial role in bringing about the near-eradication of polio globally. In the early 20th century, the United States and many other countries experienced regular outbreaks of polio. Thousands of children were left paralyzed, and public fear of the disease was immense. Since polio could spread through water, food, and physical contact, summer months—when children were more likely to be outdoors—were often met with heightened anxiety. Quarantines, closures of public spaces, and iron lungs (machines used to assist patients with paralyzed respiratory muscles) became symbols of the polio epidemic. By the mid-20th century, it became evident that the only way to combat polio was through vaccination. However, creating a safe and effective vaccine was a significant scientific challenge. This was the context in which both Dr. Jonas Salk and Dr. Albert Sabin began their work.

Dr. Jonas Salk was born in New York City in 1914. A medical researcher by training, Salk initially worked on influenza vaccines before turning his attention to polio. At the time, the prevailing scientific belief was that live viruses were necessary to create immunity through a vaccine. However, Salk chose a different path—he pursued the development of an inactivated polio vaccine (IPV) using a killed version of the poliovirus. Salk’s approach was innovative because he believed that even a killed virus could trigger an immune response strong enough to protect individuals from infection without the risk of causing disease. After years of research, his vaccine was ready for testing in the early 1950s. The March of Dimes, a nonprofit organization, played a crucial role in supporting Salk’s work, funding his research and helping coordinate mass trials. In 1954, the Salk vaccine was tested on more than one million children in what was called the "polio pioneers" trial. The results were overwhelmingly positive. On April 12, 1955, it was announced that the Salk vaccine was safe, effective, and potent, marking a watershed moment in medical history. The vaccine was immediately distributed, and within just a few years, the incidence of polio in the United States plummeted. Salk became a national hero, and his work saved countless lives. The Salk vaccine’s key strength was its safety. Because the virus used in the vaccine was inactivated, there was no risk of vaccine-derived infection. However, one limitation was that it had to be administered by injection, which required skilled healthcare workers and was more costly and difficult to deliver on a large scale, particularly in developing countries.

While Salk’s vaccine was a breakthrough, Dr. Albert Sabin believed there was a better approach. Born in Poland in 1906 and later moving to the United States, Sabin was a virologist who, like Salk, was determined to find a solution to polio. However, Sabin believed that an oral polio vaccine (OPV) using a live, attenuated (weakened) virus would be more effective in the long term. Sabin argued that a live-virus vaccine would stimulate both systemic immunity (through the blood) and intestinal immunity (in the gut), where polio replicated, offering more comprehensive protection. Sabin’s work began in the late 1940s, but his vaccine took longer to develop and gain approval than Salk’s. Sabin’s live-virus vaccine was tested in the Soviet Union and Eastern Europe in the late 1950s, with strong success. By 1961, the Sabin oral polio vaccine was approved for use in the United States and other countries. The key advantage of the Sabin vaccine was that it could be administered orally, making it much easier to distribute, particularly in large-scale vaccination campaigns. The oral vaccine could be given by volunteers, did not require sterile needles, and was cheaper to produce and deliver. It also had the ability to induce "herd immunity," as vaccinated individuals could pass the weakened virus to others, indirectly immunizing unvaccinated people. However, there was a potential risk associated with the live-virus vaccine. In rare cases, the weakened virus could revert to a more virulent form, causing vaccine-derived poliovirus (VDPV). Despite this risk, the Sabin vaccine was widely adopted, especially in global efforts to eradicate polio.

Both Salk and Sabin’s vaccines had a profound impact on global health, but their contributions were complementary. In developed countries like the U.S., where polio was quickly brought under control following the introduction of Salk’s vaccine, the Sabin vaccine helped solidify the gains by making it easier to vaccinate large populations. In developing countries, the ease of oral administration made Sabin’s vaccine the backbone of global polio eradication efforts. The combined use of the Salk and Sabin vaccines has resulted in the near-elimination of polio worldwide. In 1988, the World Health Organization (WHO) launched the Global Polio Eradication Initiative, using both vaccines to combat the disease. By the 21st century, polio had been eradicated in most countries, with only a few areas still reporting cases, primarily due to challenges in vaccine access and distribution. The two vaccines continue to play a vital role in this effort, with the Salk IPV now being used in many parts of the world due to its superior safety profile, while the Sabin OPV remains crucial in certain areas due to its ease of administration and cost-effectiveness.