Asian flu epidemic of the 1950s

The Event Global pandemic of a new strain of type-A influenza virus

Date Peaked between September and November, 1957, followed by a second wave in 1958

The 1957 flu was a global pandemic of explosive proportions, the worst since 1918, with elevated death rates among the elderly and very young.

The Asian flu of 1957 sickened millions of people globally and was the most dramatic epidemiological event since the influenza pandemics of 1918 and 1889-1890. The 1957 flu variety was the most serious of three influenza epidemics affecting North America during the 1950’s. A strain of influenza, which evolved by genetic drift, appeared in China in early 1957, and by late May, it had spread along transportation routes to Hong Kong, Japan, the Philippines, Malaysia, and Indonesia.

The virus entered the United States in June at the Naval Training Station in San Diego, California, as well as aboard a naval vessel deployed along the East Coast out of Newport, Rhode Island. It appeared in additional epicenters in Montana, Arizona, and Florida and by mid-summer was diffusing rapidly inland from the West, East, and Gulf coasts. The disease was geographically localized rather than frontal in its spread. Scientists believe that a small number of infected carriers known as “super-spreaders” may have unwittingly created multiple epicenters of disease throughout North America, especially in heavily populated urban areas.

The full pandemic exploded in both Canada and the United States from September through November; only isolated areas such as parts of Appalachia, interior Texas , the northern Plains, and lightly populated expanses of Canada escaped the worst of the disease. The Maritime Provinces were hardest hit in Canada, while Ontario and British Columbia faired much better, and the other provinces fell in between. The flu dissipated in North America by late autumn, but in the United States, the deadly siege in the fall was followed by another wave in early 1958. Except for the Ontario city of Montreal, Canada escaped the second onslaught. Overall, the flu epidemic in Canada was similar to the epidemic in the United States, with localized outbreaks, mostly from influxes of infected persons into population centers.

The 1957 influenza exhibited a normal age-mortality curve, with mortality the highest among the elderly. Death was normally a result of bacterial pulmonary complications and, in many cases, influenza may have hastened death to those with chronic cardiorespiratory ailments. Morbidity and mortality statistics were a reflection of the intertwining forces of viral strength and human vulnerability. The disease killed about eighty thousand persons in the United States, while Canada experienced a somewhat lower mortality rate.

Impact

The epidemic led to controversy over the feasibility and logistics of national inoculation programs. The federal governments did not mobilize to mass vaccinate the American and Canadian populations. A vaccine was developed, but there were diagnostic and distribution problems. This epidemiological event drew greater attention to disease surveillance and diagnosis, vaccine development, and research into the mechanisms of the type-A virus. Research showed its link to the Spanish flu of 1918, the most deadly epidemic in American history, and researchers continue their search for the genetic reservoirs and carriers of these strains. Birds, pigs, and human beings in South China intermingle in a viral breeding ground and have a suspected link to the 1957 flu.

Bibliography

McDonald, J. C. “Influenza in Canada.” Canadian Medical Association Journal 97 (1967): 522-527. A summary of morbidity and mortality in Canada, primarily 1946 through 1965.

Pyle, Gerald F. The Diffusion of Influenza: Patterns and Paradigms. Totowa, N.J.: Rowman & Littlefield, 1986. Covers U.S. patterns of morbidity and mortality, with emphasis on origins and diffusion mechanisms.