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Institut für Medizinische Biometrie
und Statistik (IMBI)

Swissnoso - Swiss Point Prevalence Survey about Healthcare‐associated Infections


Prevalence surveys to measure the burden of healthcare‐associated infections (HAI) have a long tradition in the field of infection prevention and control (IPC). The pioneering Study on the Efficacy of Nosocomial Infection Control (SENIC) project, initiated in the 1970s by the US Centers for Disease Control and Prevention (CDC), unequivocally proved the benefit of HAI surveillance. The method was a point prevalence survey based on a stratified random sample of patients from 338 US hospitals, and HAIs were detected by thorough patient chart review. The HAI prevalence at that time was estimated at approximately 5.2%. In 1981, the World Health Organization (WHO) convened an advisory group on the surveillance, control, and prevention of HAI. The group specifically recommended the conduct of HAI prevalence surveys to assess the burden of the problem in different parts of the world. Results of this initiative were later published based on prevalence data gathered between 1983 and 1985 from 47 hospitals in 14 countries. At the same time, an increasing number of countries started to conduct national or regional prevalence surveys. Most recently, the European Centre for Disease Prevention and Control (ECDC), as well as the CDC, performed large point prevalence surveys in Europe and the United States based on methodologies published in separate pilot studies. The results of both surveys were published recently. Most local, regional, and national surveys used the point prevalence methodology, that is, only HAIs active on the day of the survey were taken into account. However, some studies in Italy, Switzerland, and the United States used the period prevalence method, that is, not only were HAIs active on the day of the survey accounted for, but those active during a predefined period before the survey day were also assessed. Some surveys, such as the first Spanish prevalence survey of the Estudio de Prevalencia de las Infecciones Nosocomiales en España (EPINE) network, combined point prevalence (active infection on the day of survey) with extrinsic risk factors present in the 7 days before the survey. Both methodologies have advantages and disadvantages. While a period prevalence survey will allow capture of more HAIs, especially those of short duration, it is methodologically “less pure,” since it mixes the concepts of prevalence and incidence, and it is also more time‐consuming than a pure point prevalence survey. Today, there is consensus that the point prevalence method is sufficient for surveillance purposes and that it is easier to perform. Period prevalence surveys have almost completely disappeared from the literature and for benchmarking purposes, the point prevalence is the choice.

Work plan

The work will be conducted in two separate work packages:

Work package 1: The prevalence survey (CH‐PPS) in Switzerland

  • to obtain representative data on HAI in acute care hospitals in Switzerland
  • to obtain data on antibiotic use on acute care hospitals in Switzerland
  • to establish a network of conducting PPS in Switzerland in the future
  • to benchmark data on HAI and antibiotic consumption with the concurrently performed ECDCPPS II

Work package 2: Estimation of attributable mortality and costs of healthcare-associated infections

  • to estimate attributable mortality from healthcare‐associated infections for Switzerland
  • to estimate costs for healthcare‐associated infections for Switzerland


Dr. Sam Doerken

phone: +49 761 203 7703