unlike influenza a viruses of 1968-1976 with high immunogenic and reproductive activities , influenza a viruses isolated in the ussr during epidemics of 1977-1978 , 1979 , and 1980 were either poorly immunogenic and unable for reproduction in the throat after oral administration , or , like variants of 1979 , intensively multiplied in the throat but did not spread actively into the nasal epithelium and produced no immunological protection in orally vaccinated humans .
C0521367
throat
C0031354
throat