Final answer:
The iron lung was a vital respiratory aid for those afflicted by polio, which caused muscle paralysis and respiratory failure. The invention was crucial before the successful development and widespread administration of the polio vaccine, which has nearly eradicated the disease globally.
Step-by-step explanation:
The iron lung is a device historically associated with polio, an infectious disease that can cause muscle paralysis, particularly affecting the muscles used for breathing. To assist those who were unable to breathe independently due to polio, the iron lung mechanically mimicked the breathing process. Patients would lie within this cylindrical chamber, which would create a vacuum to stimulate the expansion and contraction of the chest cavity, effectively enabling respiration. Polio epidemics in the first half of the 20th century led to many becoming reliant on such devices.
During the polio epidemics, the fear of muscle paralysis gripped the general population, making technological inventions like the iron lung critical for survival. The availability of iron-lung wards, as evidenced by photos from the period, showcased the severity of the situation. Despite the grim scenario, the discovery of the polio vaccine by Jonas Salk, using a killed virus and later, a live vaccine, marked a turning point. Immunization campaigns throughout the 1950s and 1960s significantly reduced the disease's incidence, demonstrating the power of preventative medicine and leading to the virtual eradication of polio in many countries.