AN EPIDEMIC OF INFLUENZA. RESULTS OF PROPHYLACTIC INOCULATION OF A COMPLEX INFLUENZA A-DISTEMPER VACCINE 1

Abstract

Clinical and epidemiological observations were made at the Univ. of California Medical Center during an epidemic of influenza A which occurred in San Francisco in Nov. and Dec. 1940 and Jan. 1941. Antibody studies indicated that influenza A was the causative agent in 75% of the cases. Influenza B was not present. No distinguishing clinical features were observed between cases of influenza A and cases of influenza of unknown etiology which occurred simultaneously in this epidemic. Subcut. inoculation of 273 of a total of 1213 individuals was performed with a mixed influenza A[long dash]distemper vaccine, at the beginning of the epidemic. A marked reduction in incidence of influenza A occurred in the vaccinated group as compared to the controls. The incidence of influenza in the control groups was between 25 and 43% as compared to 13 and 15% in those inoculated. The observations suggest that a measure of protection was afforded by vaccination but they do not permit the conclusion that efficient protection resulted.