title: The incidence of invasive pneumococcal serotype 3 disease in the Danish population is not reduced by PCV-13 vaccination.
abstract: Since 2010, Denmark has included the 13-valent pneumococcal conjugated vaccine (PCV-13) in the childhood immunization programme. However, serotype 3 remains as an important cause of invasive pneumococcal disease (IPD) in Denmark. IPD surveillance data (1999-2016) was used to calculate the incidence and age-distribution of serotype 3 IPD, and the effect of PCV-13 on serotype 3 IPD incidence was examined. The incidence of serotype 3 IPD in the age group below 65 years was 0.51/100,000 pre PCV-13, and 0.45/100,000 post PCV-13. In the group 0-4 years, serotype 3 IPD incidence was 0.28/100,000 pre PCV-13, and 0.16/100,000 post PCV-13. Serotype 3 IPD incidence in the elderly showed a mean of 4.27/100,000 pre PCV-13, and 4.32/100,000 post PCV-13. PCV-13 childhood immunization in Denmark has not lead to a reduction of the incidence of IPD caused by serotype 3. The reason behind this missing effect needs to be investigated further.
authors.affiliation: Neisseria and Streptococcus Reference Laboratory, Department of Microbiology and Infection Control, Statens Serum Institut, Copenhagen, Denmark.
authors.forename: Hans-Christian
authors.initials: HC
authors.lastname: Slotved
authors.affiliation: Neisseria and Streptococcus Reference Laboratory, Department of Microbiology and Infection Control, Statens Serum Institut, Copenhagen, Denmark.
authors.forename: Tine
authors.initials: T
authors.lastname: Dalby
authors.affiliation: Neisseria and Streptococcus Reference Laboratory, Department of Microbiology and Infection Control, Statens Serum Institut, Copenhagen, Denmark; Department of Infectious Diseases, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
authors.forename: Zitta Barrella
authors.initials: ZB
authors.lastname: Harboe
authors.affiliation: Department of Infectious Disease Epidemiology, Statens Serum Institut, Copenhagen, Denmark.
authors.forename: Palle
authors.initials: P
authors.lastname: Valentiner-Branth
authors.affiliation: Department of Infectious Disease Epidemiology, Statens Serum Institut, Copenhagen, Denmark.
authors.forename: Victoria Fernandez de
authors.initials: VF
authors.lastname: Casadevante
authors.affiliation: Department of Infectious Disease Epidemiology, Statens Serum Institut, Copenhagen, Denmark.
authors.forename: Laura
authors.initials: L
authors.lastname: Espenhain
authors.affiliation: Neisseria and Streptococcus Reference Laboratory, Department of Microbiology and Infection Control, Statens Serum Institut, Copenhagen, Denmark.
authors.forename: Kurt
authors.initials: K
authors.lastname: Fuursted
authors.affiliation: Neisseria and Streptococcus Reference Laboratory, Department of Microbiology and Infection Control, Statens Serum Institut, Copenhagen, Denmark.
authors.forename: Helle Bossen
authors.initials: HB
authors.lastname: Konradsen
keywords: Immunology; Infectious diseases; Medicine