Usefulness of seroconversion rates for comparing infection pressures between countries

Epidemiol Infect. 2011 Apr;139(4):636-43. doi: 10.1017/S0950268810000750. Epub 2010 Apr 12.


Salmonella is a frequent cause of foodborne illness. However, since most symptomatic cases are not diagnosed, the true infection pressure is unknown. Furthermore, national surveillance systems have different sensitivities that limit inter-country comparisons. We have used recently developed methods for translating measurements of Salmonella antibodies into estimates of seroincidence: the frequency of infections including asymptomatic cases. This methodology was applied to cross-sectional collections of serum samples obtained from the general healthy population in three European countries. Denmark and The Netherlands had the lowest seroincidence (84,169 infections/1000 person-years), whereas Poland had the highest seroincidence (547/1000 person-years). A Bayesian method for obtaining incidence rate ratios was developed; this showed a 6·3 (95% credibility interval 3·3-12·5) higher incidence in Poland than in Denmark which demonstrates that this methodology has a wider applicability for studies of surveillance systems and evaluation of control programmes.

Publication types

  • Comparative Study
  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Bacterial / blood*
  • Cross-Sectional Studies
  • Denmark / epidemiology
  • Epidemiologic Methods
  • Foodborne Diseases / diagnosis*
  • Foodborne Diseases / epidemiology*
  • Foodborne Diseases / microbiology
  • Humans
  • Incidence
  • Netherlands / epidemiology
  • Poland / epidemiology
  • Salmonella Infections / diagnosis*
  • Salmonella Infections / epidemiology*
  • Seroepidemiologic Studies


  • Antibodies, Bacterial