Changes in the antibody status of a population following epidemic infection by influenza virus A2/Hong Kong/1/68

Publisher Website
Google Scholar
Abstract
SUMMARY The haemagglutinin of influenza virus A 2/Hong Kong/1/68 was shown to be markedly different from that of previously isolated A 2 virus strains. No haemagglutination-inhibiting (HI) antibody to A 2/Hong Kong/1/68 virus was detected in serum specimens collected in 1966 from persons aged 60 years or less. In contrast, HI antibody tests with 270 sera collected in 1968 indicated that 9·6% had demonstrable HI antibody at low titres, and 35·2% of 454 postepidemic (1969) sera had demonstrable HI antibody at relatively high titres. Most sera from persons aged 80 years and more collected in 1968 and 1969 had demonstrable HI anti-body to influenza virus A 2/Hong Kong/1/68. No HI antibody to the Hong Kong virus was detected in pre-epidemic sera from children aged 6 months to 3 years, whereas 32 % of postepidemic sera had HI antibody. The acquisition of HI antibody to A 2/Hong Kong/1/68 was not accompanied by an increase hi the incidence or titres of HI antibody to heterotypic A 2 influenza viruses. For sera from children aged 4–11 years, an increase of HI titre to heterotypic A 2 influenza was found.