Hong Kong influenza: clinical, microbiologic, and pathologic features in 127 cases

During an epidemic, in November and December 1968, the influenza A Hong Kong/68 virus was isolated from 127 adult patients. The procedures for isolation and identification of this virus are described. The clinical manifestations were similar to those of Asian influenza in 1957. Pneumonia was a complication in 20 cases. Based on roentgenograms, these cases were separated into the following two distinct syndromes: localized pneumonia (ten cases), either bacterial or viral, with low mortality (two deaths); and bilateral or diffuse pneumonia (ten cases), a primary influenza virus pneumonia, with high mortality (six deaths). Staphylococcus aureus or Pseudomonas aeruginosa infection was present in six of the eight fatal cases. Patients who were elderly, had associated chronic disease, or were hospitalized with other illnesses were most prone to develop pneumonia. Current methods of influenza control are discussed.