Hong Kong Flu Of 1968: A Virus In The US

Hong Kong flu of 1968 was the third flu pandemic in the twentieth century followed Spanish flu of 1918 and Asian flu of 1957 (Rogers). In early 1968, the first case of the Hong Kong flu was founded in Hong Kong. In the U.S., the virus was first detected in September 1968. The flu killed around 33,800 people in the U.S. between September 1968 and March 1969 (“Pandemic”).

It supposed that the Hong Kong flu may have originated in China. The virus caused a very large epidemic in Hong Kong and spread to other countries. Although its spread decreased in the winter of 1968-69, epidemics broke out in lots of countries. Unlike other sharp epidemics, the Hong Kong flu spread slowly in many countries (Cockburn). There are several reasons that relatively small number of people in the United States died due to the flu. Because the Hong Kong flu virus was similar to the Asian virus of 1957 pandemic flu, people might have some immunity against the Hong Kong flu virus. Also, the Hong Kong flu

Influenza A types cause the most problems in humans, but influenza B virus have only one type (“Flu”). Influenza A has some subtypes which are determined by a combination of the 9 neuraminidase (NA) and 16 known hemagglutinin (HA) genes that code for the viral surface proteins or envelope (Tang). The possible combinations make different influenza A subtypes such as H1N1, H3N2 and H5N1 (“Influenza”). The Hong Kong flu virus is influenza A subtype H3N2 (Rogers). The viral surface proteins such as HA and NA play an important role in viral entry and escape from the respiratory epithelial cells of human body within which the virus replicates. The influenza virus evolve quickly under host immunological selection pressure when the human immune system responses to the virus. It makes further new antigenicity allowing the virus to constantly escape from the existing host immunity developed from previous vaccination or infection