Prevention of Influenza and other Respiratory Diseases
Technical Report,01 Feb 1978,30 Jan 1979
COLORADO UNIV MEDICAL CENTER DENVER DENVER United States
Pagination or Media Count:
An explosive epidemic of H1N1 influenza occurred at Lowry AFB during February 1978. No H1N1 vaccine had been available and personnel under 25 were almost uniformly seronegative. Influenza febrile attack rates were estimated to be about 30 in students, who ranged in age from 17 to 23. An additional 20 were probably infected during the epidemic. The permanent party, most of which is over 25 years of age had far lower attack rates than the students. A small number of cases of H3N2 influenza occurred between 30 November 1977 and 30 January 1978, but the spread of this disease was very limited in this vaccinated population. The H1N1 virus strains differed from H3N2 strains in many ways. Isolation and identification were more difficult and lack of avidity of the prototype AUSSR9077 strain created difficulty in serodiagnosis. The most useful antigen for HI tests was an ether-split vaccine concentrate PD prepared from AUSSR9278 Surveys of HI antibody levels of military and civilian populations between 17 and 24 years of age indicated that approximately one half had been infected during or following the February 1978 epidemic. Studies of experimental H1N1 vaccines of 60 microgram and 20 microgram potencies showed that the former, whether split or whole virus, produced seroconversion in a very high proportion of persons.