History of Poliomyelitis - Epidemics

Epidemics

Major polio epidemics were unknown before the 20th century; localized paralytic polio epidemics began to appear in Europe and the United States around 1900. The first report of multiple polio cases was published in 1843 and described an 1841 outbreak in Louisiana. A fifty-year gap occurs before the next U.S. report—a cluster of 26 cases in Boston in 1893. The first recognized U.S. polio epidemic occurred the following year in Vermont with 132 total cases (18 deaths), including several cases in adults. Numerous epidemics of varying magnitude began to appear throughout the country; by 1907 approximately 2,500 cases of poliomyelitis were reported in New York City.

On Saturday, June 17, 1916 an official announcement of the existence of an epidemic polio infection was made in Brooklyn, New York. That year, there were over 27,000 cases and more than 6,000 deaths due to polio in the United States, with over 2,000 deaths in New York City alone. The names and addresses of individuals with confirmed polio cases were published daily in the press, their houses were identified with placards, and their families were quarantined. Dr. Hiram M. Hiller, Jr., was one of the physicians in several cities who realized what they were dealing with, but the nature of the disease remained largely a mystery. The 1916 epidemic caused widespread panic and thousands fled the city to nearby mountain resorts; movie theaters were closed, meetings were canceled, public gatherings were almost nonexistent, and children were warned not to drink from water fountains, and told to avoid amusement parks, swimming pools, and beaches. From 1916 onward, a polio epidemic appeared each summer in at least one part of the country, with the most serious occurring in the 1940s and 1950s. In the epidemic of 1949, 2,720 deaths from the disease occurred in the United States and 42,173 cases were reported and Canada and the United Kingdom were also affected.

Prior to the 20th century polio infections were rarely seen in infants before 6 months of age and most cases occurred in children 6 months to 4 years of age. Young children who contract polio generally suffer only mild symptoms, but as a result they become permanently immune to the disease. In developed countries during the late 19th and early 20th centuries, improvements were being made in community sanitation, including improved sewage disposal and clean water supplies. Better hygiene meant that infants and young children had fewer opportunities to encounter and develop immunity to polio. Exposure to poliovirus was therefore delayed until late childhood or adult life, when it was more likely to take the paralytic form.

In children, paralysis due to polio occurs in 1/1000 cases, while in adults, paralysis occurs in 1/75 cases. By 1950, the peak age incidence of paralytic poliomyelitis in the United States had shifted from infants to children aged 5 to 9 years; about one-third of the cases were reported in persons over 15 years of age. Accordingly, the rate of paralysis and death due to polio infection also increased during this time. In the United States, the 1952 polio epidemic would be the worst outbreak in the nation's history, and is credited with heightening parents’ fears of the disease and focusing public awareness on the need for a vaccine. Of the 57,628 cases reported that year 3,145 died and 21,269 were left with mild to disabling paralysis.