Jong JC de ,
Bestebroer TM ,
Bijlsma K ,
Verweij C
59 p
in Dutch
1994
Toon Nederlands
English Abstract Influenza virus is subject to frequent antigenic
changes. As a consequence, the World Health Organization (WHO) operates a
world-wide laboratory network to monitor these changes. RIVM participates
in this system. It isolates influenza virus strains from clinical specimens
obtained from a sentinel station network of general practitioners. It also
compares Dutch virus strains with foreign virus strains and with the virus
strains used in the current influenza vaccine. The results are reported to
the WHO and to the Ministry of Health of the Netherlands. The results of
such comparisons enable the Dutch health authorities to consider adaptations
of the WHO-proposal about the vaccine for the next season to the
epidemiological situation in the Netherlands. A total of 256 influenza A
virus strains isolated in 1990-1992 in the Netherlands and other countries
were analysed by haemagglutination-inhibition (HI) tests using ferret
antisera and monoclonal antibodies and, partly, by determination of the
nucleotide sequences of the haemagglutinin gene (HA1). In the season
1991/92, most strains belonged to the subtype A(H3N2), a minority to the
subtype A(H1-N1). The overall antigenic structure was similar to that of
the corresponding vaccine strain for both subtypes. This means that the
influenza vaccine will have rendered optimal protection against the
circulating virus strains in 1991/92. A markedly heterogeneous geographic
distribution was noted with the two most frequently isolated HI-variants of
subtype A(H3N2). One prevailed in the Netherlands and in Spain, the other
in Sweden, France, and the United States. Even within the Netherlands the
proportions of the two variants showed regional variation. This
heterogeneity did not have implications for the vaccine
efficacy.
