title: Estimating the impact of vaccination using age-time-dependent incidence rates of hepatitis B.
abstract: The objective of this study was to model the age-time-dependent incidence of hepatitis B while estimating the impact of vaccination. While stochastic models/time-series have been used before to model hepatitis B cases in the absence of knowledge on the number of susceptibles, this paper proposed using a method that fits into the generalized additive model framework. Generalized additive models with penalized regression splines are used to exploit the underlying continuity of both age and time in a flexible non-parametric way. Based on a unique case notification dataset, we have shown that the implemented immunization programme in Bulgaria resulted in a significant decrease in incidence for infants in their first year of life with 82% (79-84%). Moreover, we have shown that conditional on an assumed baseline susceptibility percentage, a smooth force-of-infection profile can be obtained from which two local maxima were observed at ages 9 and 24 years.
authors.affiliation: Center for Statistics, Hasselt University, Diepenbeek, Belgium. niel.hens@uhasselt.be
authors.forename: N
authors.initials: N
authors.lastname: Hens
authors.forename: M
authors.initials: M
authors.lastname: Aerts
authors.forename: Z
authors.initials: Z
authors.lastname: Shkedy
authors.forename: P
authors.initials: P
authors.lastname: Kung'u Kimani
authors.forename: M
authors.initials: M
authors.lastname: Kojouhorova
authors.forename: P
authors.initials: P
authors.lastname: van Damme
authors.forename: Ph
authors.initials: P
authors.lastname: Beutels
mesh_terms: D002031:Bulgaria / Q000453:epidemiology; D003140:Communicable Disease Control; D006509:Hepatitis B / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control*; D017325:Hepatitis B Vaccines / Q000008:administration & dosage*; D006515:Hepatitis B virus / Q000276:immunology*; D006801:Humans; D015994:Incidence; D015233:Models, Statistical; D014611:Vaccination
chemical_list: D017325:Hepatitis B Vaccines