Federal officials are now stepping up to monitor and potentially fight the spread of polio.

The New York City Health Department distributes the oral, Sabin-type polio vaccine in this file photograph. His came first, and then Albert Bruce Sabin introduced an oral vaccine in the United States in the 1960s that replaced Salk’s. He spoke of the iron lung, used on some polio patients, and remarked on how frightening they looked. In the image below, two young children are in an iron lung, a type of pressure ventilator that began use in the 1920s. AdTwo little girls lay in Iron Lung Machines while being treated for Polio.

First- and second-graders line up for Salk Polio vaccine shots on April 23, 1955. Regardless of where anyone stands on the matter, we know that vaccinations have been protecting us from diseases for decades. In 1921, the United States recorded 206,000 cases, which resulted in 15,520 deaths, according to the History of Vaccines website. According to the CDC, polio was once one of the most feared diseases in the U.S. Since 1979, there have been no polio cases that originated in the U.S.