title: Reply to letter to the Editor from S. C. Arya and N. Agarwal.
authors.affiliation: Epidemiology, Biostatistics and Prevention Institute, Division of Infectious Diseases, University of Zurich, Switzerland.
authors.forename: Phung
authors.initials: P
authors.lastname: Lang
authors.affiliation: Epidemiology, Biostatistics and Prevention Institute, Division of Infectious Diseases, University of Zurich, Switzerland.
authors.forename: Christoph
authors.initials: C
authors.lastname: Hatz
authors.affiliation: Epidemiology, Biostatistics and Prevention Institute, Division of Infectious Diseases, University of Zurich, Switzerland.
authors.forename: Fabio
authors.initials: F
authors.lastname: Valeri
mesh_terms: D037001:Directive Counseling; D006801:Humans; D017589:Immunization Programs; D010594:Pharmacies; D014611:Vaccination / Q000706:statistics & numerical data*