Influenza surveillance in Norway

Dr. Hans Blystad (hans.blystad@fhi.no)

Norwegian Institute of Public Health

November 2005

Influenza surveillance Norway

• From 1975 to 1998 aggregated data (no of cases) were collected weekly from all doctors

• Since 1999 a sentinel surveillance system introduced with 201 selected reporting units from all parts of Norway. Reporting weekly from week 40 till week 20 the following year

• Voluntary reporting system from laboratories on diagnosed influenzavirus

7

9

11

8

1111

8

14

14

97

9

10

9 9

11

16

17

10

1

Influenza reporting units i Norway

(n=201)

Data collected in the influenza season by 201 reporting units (by age group):

• no. of cases of influenzalike illness per week

• no. of total patients treated per week

• total number of patients on the doctor`s list

Influenza surveillance Norway – weekly reporting in the influenza season

Reported data influenza season 1999-2005

week