Did the dutch pneumococcal vaccination campaign decrease the need for antibiotics in children?

Background: Streptococcus pneumoniae is responsible for a significant amount of respiratory infections and acute otitis media (AOM) and use of antibiotics in children. In June 2006 a four-dose 7-valent pneumococcal vaccination campaign (PVC) was introduced in the Netherlands; 94% of children born after April 2006 were vaccinated. Although within the first years after PVC there was a decrease in invasive pneumococcal disease (IPD), it was followed by an increase in IPD caused by non-vaccine serotypes, which might lead to decreased vaccine effectiveness in terms of antibiotic use. Objectives: To estimate pneumococcal vaccine effectiveness, we will analyse the trends of the antibiotics use for AOM and pneumonia in children before and after PVC. Methods: This is an ecological study performed in children 0-5 years of age. The data comes from IADB.nl database, which contains pharmacy-dispensing data from community pharmacies in the Netherlands. The outcome is expressed as monthly proportion of the users of amoxicillin, azithromycin or cotrimoxazol out of the total population. Children born before 1 April 2006 are seen as unvaccinated, and children born after this date are seen as vaccinated. By estimating regression coefficients from segmented regression analysis we will assess whether the level and trend of antibiotic use before and after the PVC has changed noticeably (pvalue of <.05 indicating the change). The analysis will be performed for age groups of children of 0, 1, 2, 3, 4 and 5 years old and controlled for sex, underlying medical conditions and seasonal effects. Results: We expect to detect an immediate decrease in antibiotic use after the introduction of PVC followed by an increase due to the incidence in non-vaccine serotypes of S. pneumoniae. Conclusions: The results will give an indication on the effectiveness of the pneumococcal vaccination campaign in the Netherlands with regard to the antibiotic use.