Monitoring of influenza in the EISS European network member countries from October 2000 to April 2001.

In countries covered by the European Influenza Surveillance Scheme (EISS), the 2000-2001 winter was marked mainly by the spread of influenza A(H1N1) viruses. Influenza B, which globally represented a minority of cases, was common later in the season and predominant in Great Britain, Ireland, and Portugal. Influenza activity was at its maximum during the period of January and February/March 2001 with little time lag between countries (maximum four weeks). Overall, the morbidity rates reported were much lower than for the previous season, illustrating a moderate level of influenza activity.