Consultations for Influenza-Like Illness in Primary Care in The Netherlands: A Regression Approach

To estimate the general practitioner (GP) consultation rate attributable to influenza in The Netherlands. Regression analysis was performed on the weekly numbers of influenza-like illness (ILI) GP consultations and laboratory reports for influenza virus types A and B and 8 other pathogens over the period 2003–2014 (11 influenza seasons; week 40–20 of the following year). In an average influenza season, 27% and 11% of ILI GP consultations were attributed to infection by influenza virus types A and B, respectively. Influenza is therefore responsible for approximately 107 000 GP consultations (651/100 000) each year in The Netherlands. GP consultation rates associated with influenza infection were highest in children under 5 years of age, at 667 of 100 000 for influenza A and 258 of 100 000 for influenza B. Influenza virus infection was found to be the predominant cause of ILI-related GP visits in all age groups except children under 5, in which respiratory syncytial virus (RSV) infection was found to be the main contributor. The burden of influenza in terms of GP consultations is considerable. Overall, influenza is the main contributor to ILI. Although ILI symptoms in children under 5 years of age are most often associated with RSV infection, the majority of visits related to influenza occur among children under 5 years of age. •Seasonal influenza epidemics result in an excess of GP visits, hospitalizations, and deaths each winter. Because routine laboratory testing is rare in these patients, estimating the burden associated with individual respiratory pathogens is challenging.•Using Dutch data sources on influenza-like illness GP consultations and laboratory confirmations, we estimated the proportion of GP consultations attributable to influenza and other respiratory pathogens.•This study provides detailed estimates on the burden of influenza under the current vaccination program. These estimates can serve as input for future transmission models on new prevention strategies for influenza in The Netherlands.