Vaccine
Volume 27, Issue 22, Pages 2905-3012 (14 May 2009)
http://www.sciencedirect.com/science/journal/0264410X

Human papillomavirus immunisation of adolescent girls and anticipated reporting of immune-mediated adverse events
Pages 2954-2958
Torbjörn Callréus, Henrik Svanström, Nete Munk Nielsen, Sigrid Poulsen, Palle Valentiner-Branth, Anders Hviid
Abstract
Determining incidence rates of potential adverse events before and after an immunisation programme is initiated, provides a useful framework for the evaluation of vaccine safety concerns. Human papillomavirus vaccination (HPV) of adolescent girls has recently been introduced in Denmark. Using a nationwide hospitalisation registry we estimated incidence rates of immune-mediated disorders before HPV vaccination in a cohort of 418,289 Danish girls aged 12-15 years. We further estimated the expected number of cases of immune-mediated disorders occurring in temporal relationship to a hypothetical HPV vaccination schedule purely by chance. Our results and analytical approach provides a framework for the evaluation of adverse event reports following immunisation of adolescent girls.