A health worker in Karachi administers polio drops — the oral vaccine — on February 3, the first day of a nationwide polio vaccination campaign. The country, one of only two where wild polio circulates, has seen a rise in cases due to issues with vaccination campaigns. Asif Hassan/AFP via Getty Images hide caption
A nurse administers polio vaccine drops to a young Palestinian patient at the Nasser hospital in Khan Yunis in the southern Gaza Strip on Saturday amid the ongoing conflict between Israel and the Hamas militant group. Jihad Al-Sharafi/AFP via Getty Images hide caption
Palestinian children are sitting on a street flooded with sewage water in Deir el-Balah, in the central Gaza Strip, on July 23. Polio was detected in multiple samples of Gaza's wastewater a week ago and now infectious disease experts suspect there are mild cases of the disease already in the population. Majdi Fathi//NurPhoto via Getty Images hide caption
Paul Alexander, who held a Guinness World Record for living the longest with the help of an iron lung, has died. Here, medical staff stand among iron lung machines in an emergency polio ward at Haynes Memorial Hospital in Boston, Mass., on Aug. 16, 1955, when the city's polio epidemic hit a high of 480 cases. AP hide caption
A health worker administers a measles vaccine during a vaccination drive, prompted by a measles outbreak, in Navi Mumbai, India, in December 2022. A new UNICEF report finds that India has the world's largest number of children with zero doses of childhood vaccines: 2.7 million Bachchan Kumar/Hindustan Times via Getty Images hide caption
Do some people have built-in protection against a COVID infection? Laura Gao for NPR hide caption
FILE - This 2014 illustration made available by the U.S. Centers for Disease Control and Prevention depicts a polio virus particle. The polio virus has been found in New York City's wastewater in another sign that the disease, which hadn't been seen in the U.S. in a decade, is quietly spreading among unvaccinated people, health officials said Friday, Aug. 12, 2022. AP hide caption
Minda Dentler handcycling at mile 32 of The Kona Ironman in Hawaii, 2013. She's the first female wheelchair athlete to complete the Ironman World Championship. When she was an infant, her legs were paralyzed by polio. "I wish all people who may be on the fence about vaccination could really meet me," she says. "I'm a reminder to families that they should vaccinate their children." Kevin Charboneau hide caption
This carefully-worded and designed infographic from Rockland County, NY describes — in English, Spanish, Haitian Creole, and Yiddish — what polio is and that immunization is the best way to protect yourself and others. Ari Daniel for NPR hide caption
This 2014 illustration made available by the U.S. Centers for Disease Control and Prevention depicts a polio virus particle. Sarah Poser, Meredith Boyter Newlove/CDC via AP hide caption
A health worker gives a polio vaccine to a child in Karachi, Pakistan, on May 23. British health authorities on Wednesday said they will offer a polio booster dose to children aged 1 to 9 in London, after finding evidence the virus has been spreading in multiple regions of the capital. Fareed Khan/AP hide caption
A Centers for Disease Control and Prevention scientist works with polio virus material. The first case of polio in nearly decade was detected in a New York patient Thursday. The individual was unvaccinated and likely contracted the virus from an individual outside of the country. James Gathany/CDC hide caption
This 2014 illustration made available by the Centers for Disease Control and Prevention depicts a polio virus particle. On July 21, 2022, New York health officials reported a polio case, the first in the U.S. in nearly a decade. Sarah Poster and Meredith Boyter Newlove from the CDC via AP hide caption
Aerial view of the Beckton Sewage Treatment Works in London. Between February and May, U.K. scientists found several samples containing closely related versions of the polio virus in wastewater at the plant. mwmbwls/Flickr hide caption
A child receives a polio vaccine in Kampala, Uganda, on Jan. 14, 2022. Nicholas Kajoba/Xinhua News Agency via Getty Images hide caption
Left: A drawing of a human with a cow head holding a needle menacingly toward a child as he administers a tainted smallpox vaccination was meant to sow distrust of smallpox vaccines. Right: Protesters against COVID-19 vaccinations hold a rally in Sydney in February. Bettman/Getty Images; Brook Mitchell/Getty Images hide caption
Elvis Presley got his polio vaccination from Dr. Harold Fuerst and Dr. Leona Baumgartner at CBS' Studio 50 in New York City on Oct. 28, 1956. The chart-topping singer took part in a March of Dimes campaign to convince teens to get vaccinated. Seymour Wally/NY Daily News Archive via Getty Images hide caption
Polio vaccinator Zeenat Parveen, holding the clipboard, and a volunteer go door-to-door to reach children in Rawalpindi, a city near the Pakistani capital of Islamabad. Diaa Hadid/NPR hide caption
A health worker administers a polio vaccine to a child in Afghanistan's Kandahar province. Taliban opposition to vaccine campaigns have left millions of children unprotected against the virus. Javed Tanveer/AFP via Getty Images hide caption
An oral polio vaccine, which contains weakened live virus, is administered in a health enter in Togo. Africa has declared that wild polio has been eradicated, but a relatively small number of cases of vaccine-derived polio persist. BSIP/Universal Images Group via Getty hide caption
Dr. Jonas E. Salk, who discovered the polio vaccine, reads with his wife and three boys in Ann Arbor, Mich., on April 11, 1955. The boys were among the first vaccinated during testing. The family was photographed the night before an announcement the vaccine was effective. Pictured from left are Jonathan, 5; Donna Salk; Peter, 11; Salk; and Darrell, 8. AP hide caption
Dr. Jonas Salk, the scientist who created the polio vaccine, administers an injection to an unidentified boy at Arsenal Elementary School in Pittsburgh, Pa., in 1954. AP hide caption
Ina Pinkney in 1948 after undergoing her first corrective surgery. Ina Pinkney hide caption