title: Severity of mumps disease is related to MMR vaccination status and viral shedding.
abstract: BACKGROUND
  During recent years, various mumps outbreaks have occurred among measles, mumps, and rubella (MMR) vaccinated persons in various countries worldwide, including the Netherlands. We studied mumps virus shedding in MMR vaccinated and unvaccinated mumps patients and related these findings to clinical data.
  
  
  METHODS
  In this study, we included 1112 mumps patients of whom diagnostic samples were tested positive in our laboratory between 1 January 2007 and 31 December 2014. We compared mumps virus shedding and severity of disease between patients who had received 2 doses of MMR (n=592) and unvaccinated mumps patients (n=195). Mumps virus shedding in saliva and urine specimens was measured by qPCR. Severity of disease was studied in a subset of patients with clinical data available.
  
  
  RESULTS
  Mumps patients who had received 2 MMR doses shed less often mumps virus in their urine than unvaccinated patients. Salivary viral loads were higher at day of onset of disease in twice MMR vaccinated patients with viruria than in twice MMR vaccinated patients without viruria. However, salivary viral loads did not significantly differ between patients who had received 2 MMR doses and unvaccinated patients. Bilateral parotitis and orchitis were less often reported in patients who had received 2 MMR doses than in unvaccinated patients. Furthermore, the prevalence of bilateral parotitis and orchitis was higher among twice MMR vaccinated patients with viruria than among twice MMR vaccinated patients without viruria.
  
  
  CONCLUSIONS
  MMR vaccination was associated with less severe disease among mumps patients. Systemic spread of virus was associated with more severe disease. The elevated salivary viral loads in patients with systemic mumps disease suggest that these patients pose a higher risk for mumps virus transmission. Our study contributes to the understanding of mumps virus pathogenesis and shows the protective effect of MMR vaccination on severity of disease.
authors.affiliation: Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA Bilthoven, The Netherlands; Department of Viroscience, Erasmus University Medical Centre, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands. Electronic address: sigrid.gouma@rivm.nl.
authors.forename: Sigrid
authors.initials: S
authors.lastname: Gouma
authors.affiliation: Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA Bilthoven, The Netherlands. Electronic address: susan.hahne@rivm.nl.
authors.forename: Susan J M
authors.initials: SJ
authors.lastname: Hahné
authors.affiliation: Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA Bilthoven, The Netherlands. Electronic address: daphne.gijselaar@rivm.nl.
authors.forename: Daphne B
authors.initials: DB
authors.lastname: Gijselaar
authors.affiliation: Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA Bilthoven, The Netherlands; Department of Viroscience, Erasmus University Medical Centre, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands. Electronic address: m.koopmans@erasmusmc.nl.
authors.forename: Marion P G
authors.initials: MP
authors.lastname: Koopmans
authors.affiliation: Centre for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA Bilthoven, The Netherlands. Electronic address: rob.van.binnendijk@rivm.nl.
authors.forename: Rob S
authors.initials: RS
authors.lastname: van Binnendijk
mesh_terms: D005260:Female; D005334:Fever / Q000453:epidemiology; D006801:Humans; D008297:Male; D022542:Measles-Mumps-Rubella Vaccine / Q000008:administration & dosage* / Q000627:therapeutic use; D009107:Mumps / Q000453:epidemiology* / Q000517:prevention & control; D009109:Mumps virus; D009426:Netherlands; D009920:Orchitis / Q000453:epidemiology; D010309:Parotitis / Q000453:epidemiology; D012463:Saliva / Q000821:virology; D014556:Urine / Q000821:virology; D014611:Vaccination / Q000706:statistics & numerical data*; D019562:Viral Load; D017201:Virus Shedding; D055815:Young Adult
chemical_list: D022542:Measles-Mumps-Rubella Vaccine
keywords: MMR vaccination; Mumps disease; Orchitis; Parotitis; Salivary viral loads; Viruria