Correspondence (reply): In Reply

We thank Drs Klinkenberg and Blohm for their contribution, which points out the high risk for cases of influenza with lethal outcomes in children with chronic comorbidities and which rightly underlines the need of annual flu vaccination in children. In order to achieve the high vaccination rate that is required to protect pediatric risk groups, we also make the case for a general recommendation for vaccinating children. However, we think that our colleagues' explanations of the protective effect of the flu vaccines are based on a misinterpretation. The morbidity rates of 4.2% (attenuated live vaccine) and 8.1% (conventional vaccine) relate to the respective total cohort of vaccinated persons, of whom 10–30% contract influenza every year. Morbidity rates of unvaccinated comparator cohorts were not included in the studies analyzed in the meta-analysis (1). In our study, we did not go into detail about the effectiveness of the attenuated live vaccine compared with placebo, for reasons of space. Depending on the degree of match between the vaccine viruses and circulating wild viruses, this is 78–83% (1). Unfortunately, this vaccine cannot be used in children younger than 2 years because of its side effect profile. As conventional vaccines are at best of moderate effectiveness in this age group, in order to protect these children high immunization rates among contacts should be aimed for, which may result in herd immunity (2).