title: Assessment of vaccine candidates for persons aged 50 and older: a review.
abstract: BACKGROUND
  The increasing life expectancy in most European countries has resulted in growth of the population 50 and older. This population is more susceptible to infectious diseases because of immunosenescence, co-morbidity and general frailty. Thus, to promote healthy aging, vaccination against vaccine-preventable-diseases could be one strategy. In addition to its possible individual benefits, vaccination may also yield social benefits, such as a lower overall cost of healthcare. Most European countries, however, offer only influenza vaccine although vaccines for pneumococcal disease, herpes zoster, pertussis, and hepatitis A are also available. Our aim is to review the knowledge of these vaccines for persons aged 50 and older and explore the arguments for expanding current vaccination programmes beyond just influenza.
  
  
  METHODS
  The evaluation model of Kimman et al. was used to assess herpes zoster, pneumococcal disease, pertussis and hepatitis A in terms of four domains: pathogen, vaccine, disease outcomes and cost-effectiveness. The sources were Dutch surveillance systems, seroprevalence studies and the international literature.
  
  
  RESULTS
  Herpes zoster, pneumococcal disease and pertussis are prevalent among persons aged 50 and older. Vaccines vary in effectiveness and have mild and self-limiting side effects. Vaccination against pneumococcal disease and pertussis causes adaptation of the responsible pathogen. For pertussis and hepatitis A, the vaccine is not registered specifically for the elderly population. Vaccination against herpes zoster and pertussis could improve quality of life, while vaccination against pneumococcal disease and hepatitis A prevents mortality. However, only vaccination against herpes zoster and pneumococcal disease appear to be cost-effective.
  
  
  CONCLUSIONS
  Vaccination can improve the health of the elderly population. As our review shows, however, the data are too incomplete to accurately judge its potential impact. More research is needed to determine how vaccination can most effectively improve the health of the growing population 50 years and older.
authors.affiliation: Department of Epidemiology, University of Groningen, Academic Medical Center Groningen, P,O, Box 30,001, Groningen 9700 RB, The Netherlands. renske.eilers@rivm.nl
authors.forename: Renske
authors.initials: R
authors.lastname: Eilers
authors.forename: Paul F M
authors.initials: PF
authors.lastname: Krabbe
authors.forename: Ted G A
authors.initials: TG
authors.lastname: van Essen
authors.forename: Anita
authors.initials: A
authors.lastname: Suijkerbuijk
authors.forename: Alies
authors.initials: A
authors.lastname: van Lier
authors.forename: Hester E
authors.initials: HE
authors.lastname: de Melker
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D003362:Cost-Benefit Analysis / Q000191:economics; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome; D014611:Vaccination / Q000191:economics / Q000379:methods* / Q000401:mortality; D014612:Vaccines / Q000191:economics / Q000627:therapeutic use*
chemical_list: D014612:Vaccines