Technical note:

• EISS collects data from week 40 to week 20 of the following year
  
  
• Epidemiological and virological details concerning the networks in EISS are presented in the public pages of this web site.
  
  
• The data presented in the EISS WEB is based on data collected during the previous week and entered into the EISS database by Thursday 9:00am (Central European Time)
  
  
• The data presented in the EISS WEB is preliminary
  
  
• The networks have two additional weeks to enter their definite data into the EISS database. This delay is due to communication methods (e.g. data is received by post) and processing times (e.g. the determination of virus subtypes)
  
  
• Differences may exist between the levels of influenza activity reported in the EISS WEB (which is preliminary data) and the levels in the public EISS maps (which is definite data)
  
  

 Last updated: 19 October 2001