Immunity comparison of both epidemic influenza virus type-A strains circulating in Brazil, in 1991 and 1995

ABSTRACT

Influenza is a viral disease characterized by a high level of virus dissemination among susceptible hosts - fowls, mammalians and humans - in epidemic periods. Antigenic variations in the viral hemagglutinin (HA) are epidemiologically important. A single radial hemolysis (SRH) method was carried to compare type-A (H3N2) viral strains isolated in the city of São Paulo, State of São Paulo, Brazil, in different periods of time (1991 and 1995). Stored sera sample collected in 1993 from 60 individuals, before and two weeks after their vaccination against A/SP/1/91 influenza virus, were evaluated by this method. Antibody levels evaluated by SRH showed no significant differences between population vaccinated with...