Description of the situation
20 February 1997
Disease Outbreak Reported
The composition for the influenza vaccine for the 1997- 1998 season was announced at a meeting of international experts that was held at the World Health Organization (WHO) headquarters in Geneva on 19 February. The three components to be included are: an A/Wuhan/359/95(H3N2)-like strain, an A/Bayern/7/95(H1N1)-like strain and a B/Beijing/184/93-like strain. In this composition the H1N1 component has been changed since last year.
During the 1997-1997 season several countries in the Northern Hemisphere reported moderate to severe influenza epidemics. Influenza activity in several countries in western Europe and in North America reached a peak during December 1997 or January 1997 whereas in central and eastern Europe activity increased around mid-January. Influenza A viruses were isolated worldwide and were almost exclusively of the influenza A(H3N2) subtype. However, most isolates from Asia were influenza B, although in Japan influenza A(H3N2) was most prevalent. In North America and parts of Europe, influenza B was frequently reported either along with, or following influenza A activity. A few laboratory confirmed cases of influenza A(H1N1) have been reported since October 1997. Further information is presented in Weekly Epidemiological Record No. 9 published on 28 February.