Does a population survey provide reliable influenza vaccine uptake rates among high-risk groups? A case-study of The Netherlands.

All European countries have recommendations for influenza vaccination among the elderly and chronically ill. However, only a few countries are able to provide data on influenza uptake among these groups. The aim of our study is to investigate whether a population survey is an effective method of obtaining vaccination uptake rates in the different risk groups and to find out what reasons people give as to why they have accepted or refused influenza vaccination and whether this varies among the risk groups. A mail questionnaire was sent out to households in The Netherlands, the response rate was 73%. This resulted in data for 4037 individuals on influenza and influenza vaccination during the 2001-2002 influenza season. The uptake rates and size of different risk groups from the panel survey were comparable with other national representative sources (from the National Information Network of GPs (LINH) and Statistics Netherlands (CBS)). The main reason cited for undergoing vaccination was the existence of a chronic condition. The main reasons for refraining from vaccination were having enough resistance to flu and ignorance about the recommendations. In The Netherlands, the GP is the main administrator of influenza vaccines. We believe that population surveys may be useful for revealing influenza vaccination uptake rates for the groups at risk. When combined with questions about reasons for undergoing vaccination, the results may provide useful policy information and can be used to direct vaccination campaigns at under-vaccinated risk groups or to target the information campaign more effectively.