THE MOLECULAR CHARACTERIZATION OF INFLUENZA-VIRUS STRAINS ISOLATED INSOUTH-AFRICA DURING 1993 AND 1994

Influenza A (H3N2) and influenza B viruses isolated recently in South Africa were analysed by partial nucleotide sequencing of the haemagglu tinin gene to examine antigenic drift of the isolates relative to the vaccine strains. The genomic analysis of the influenza B isolates reve aled a number of differences in the amino acid residues compared with those of the B/Panama/45/90 vaccine strain, and these isolates were fo und to be antigenically more closely related to B/Quindao/102/91. In b oth the 1993 and 1994 influenza A (H3N2) isolates significant drift ha d taken place compared with the H3N2 vaccine strains for those years, emphasizing the need for an influenza vaccine formulated specifically for the southern hemisphere.