title: Defining the timing of respiratory syncytial virus (RSV) outbreaks: an epidemiological study.
abstract: BACKGROUND
  Seasonal RSV infections occur every year and affect particularly children under six months of age. Passive immunoprophylaxis with monoclonal antibody Palivizumab is recommended in the period with high risk of RSV infection. This study aims to define the period for the southern part of Germany (Stuttgart area).
  
  
  METHODS
  Epidemiological analysis of the RSV situation in southern Germany from 1996 to 2004 and comparison of results with literature was made. The respiratory tract specimens were sent in for the detection of RSV mainly by paediatric clinics. Detection of RSV was carried out mainly by real-time RT-PCR or by ELISA "Pathfinder". RSV outbreaks were depicted as an absolute number and as a percentage of RSV diagnoses in a month. Onsets, offsets, peaks, duration and severity of RSV seasons were defined and analysed.
  
  
  RESULTS
  An early season with strong RSV activity (early-high phase) was followed by a weaker late season (late-low phase) in a regular biennial rhythm. However, onsets, offsets and durations of outbreaks varied significantly from year to year. RSV epidemics in southern Germany were found to oscillate in an antiphase with RSV epidemics in Finland and Sweden.
  
  
  CONCLUSIONS
  The long-term regular biennial rhythm allows predicting whether the next outbreak will be late or early and whether RSV activity will be strong or weak. Not foreseeable, however, is the precise time of increase and decrease of RSV activity. Moreover, the regular seasonal pattern may be disrupted by irregular outbreaks. Thus, activity of RSV has to be monitored every year to define the period with high risk of infection.
authors.affiliation: Institute for Virology, Infectiology and Epidemiology & Medical Diagnostic Laboratory Prof. G. Enders and Partners, Rosenbergstrasse 85, D-70 193, Stuttgart, Germany. ladwig@labor-enders.de
authors.forename: Elena
authors.initials: E
authors.lastname: Terletskaia-Ladwig
authors.forename: Gisela
authors.initials: G
authors.lastname: Enders
authors.forename: Gunnar
authors.initials: G
authors.lastname: Schalasta
authors.forename: Martin
authors.initials: M
authors.lastname: Enders
mesh_terms: D002648:Child; D004196:Disease Outbreaks; D006801:Humans; D018357:Respiratory Syncytial Virus Infections / Q000453:epidemiology*; D012307:Risk Factors; D012621:Seasons; D013997:Time Factors