Serological epidemiological studies with influenza A viruses

Abstract

Determinations were made of the age distribution of antibody to swine virus and representatives of the various families of human influenza A virus in 1961–62 collections of human sera and paired sera from forty individuals taken in 1952 and 1963:(a) The existence of cohorts of the population, each with a dominant antibody type related to strains of virus first encountered in childhood, was confirmed.(b) The basic epidemiological pattern was similar to that previously detected in 1954. However, it seemed that antibody to swine virus had been reinforced but not antibody to A and A1 strains.(c) Neutralizing and HI antibodies to A/Equine/Miami/63 virus were detected only in the sera of older people (65 years or over) collected in 1964. No antibodies were found to A/Equine/Prague/56 or two duck viruses.(d) Relatively constant levels of antibody to A, A1 and A 2 viruses were present in sera from aged persons but antibody to swine virus diminished with age. This could be attributed to a lack of swine antibody in the older females.