title: Increased risk of human parvovirus B19 infection in day-care employees: a cohort study among pregnant workers during an epidemic in Finland.
abstract: BACKGROUND
  Human parvovirus B19 (B19V) infection during early pregnancy increases the risk of miscarriage. Studies have inconsistently shown an elevated risk of infection among women with occupational contacts with children. Methodological differences, particularly in defining occupational exposure and in the type of reference group, may explain the conflicting findings.
  
  
  METHODS
  This cohort study compared B19V infections in pregnant day-care employees and healthcare professionals during a B19V epidemic in Finland. Women were identified from the files of nationwide trade unions and the National Supervisory Authority for Welfare and Health. Early-pregnancy maternal B19V IgG was analysed in 3710 women, and infections were defined as seroconversions after analysing in parallel the available umbilical cord blood samples of the 847 seronegative mothers. Independently of the serological status, the actual employment during pregnancy was assessed using registered information on employment history.
  
  
  RESULTS
  B19V infections were more common among day-care employees (22/331, 6.6%), than among those working in healthcare (12/326, 3.7%). The adjusted HRs of B19V infection, using proportional hazard regression, was 2.63 (95% CI 1.27 to 5.46) among all women and 5.59 (95% CI 1.40 to 22.4) among nulliparous women.
  
  
  CONCLUSIONS
  Day-care employees are at an increased risk of B19V infection, which warrants preventive measures.
authors: Centre of Expertise for Health and Work Ability, Finnish Institute of Occupational Health, Helsinki, Finland Department of Virology, Haartman Institute, University of Helsinki, Helsinki, Finland The Social Insurance Institution of Finland, Insurance Region for Southern Finland, Helsinki, Finland.
authors: Anita
authors: A
authors: Riipinen
authors: Centre of Expertise for Health and Work Ability, Finnish Institute of Occupational Health, Helsinki, Finland.
authors: Markku
authors: M
authors: Sallmén
authors: Department of Virology, Haartman Institute, University of Helsinki, Helsinki, Finland Laboratory Services, HUSLAB, Department of Virology and Immunology, Helsinki University Central Hospital, Hospital District of Helsinki and Uusimaa, Helsinki, Finland.
authors: Lea
authors: L
authors: Hedman
authors: Finnish Institute of Occupational Health, Centre of Creating Solutions, Helsinki, Finland.
authors: Anneli
authors: A
authors: Ojajärvi
authors: Centre of Expertise for Health and Work Ability, Finnish Institute of Occupational Health, Helsinki, Finland.
authors: Marja-Liisa
authors: ML
authors: Lindbohm
authors: Department of Virology, Haartman Institute, University of Helsinki, Helsinki, Finland.
authors: Mira
authors: M
authors: Meriluoto
authors: National Institute for Health and Welfare, Oulu, Finland.
authors: Heljä-Marja
authors: HM
authors: Surcel
authors: Centre of Expertise for Health and Work Ability, Finnish Institute of Occupational Health, Helsinki, Finland University of Helsinki, Hjelt Institute, Helsinki, Finland.
authors: Helena
authors: H
authors: Taskinen
authors: Department of Obstetrics and Gynecology, Helsinki University Central Hospital, Helsinki, Finland.
authors: Mika
authors: M
authors: Nuutila
authors: Department of Pathology, Helsinki University Central Hospital, HUSLAB, Helsinki, Finland.
authors: Riitta
authors: R
authors: Karikoski
authors: Department of Virology, Haartman Institute, University of Helsinki, Helsinki, Finland Laboratory Services, HUSLAB, Department of Virology and Immunology, Helsinki University Central Hospital, Hospital District of Helsinki and Uusimaa, Helsinki, Finland.
authors: Klaus
authors: K
authors: Hedman
authors: Department of Virology, Haartman Institute, University of Helsinki, Helsinki, Finland.
authors: Maria
authors: M
authors: Söderlund-Venermo
mesh_terms: D000328:Adult; D002648:Child; D002656:Child Day Care Centers; D015331:Cohort Studies; D005260:Female; D005387:Finland; D006282:Health Personnel; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D008875:Middle Aged; D009784:Occupational Diseases / Q000097:blood / Q000821:virology*; D016273:Occupational Exposure / Q000009:adverse effects*; D010322:Parvoviridae Infections / Q000097:blood / Q000821:virology*; D016732:Parvovirus B19, Human; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000097:blood / Q000821:virology*; D016016:Proportional Hazards Models; D012307:Risk Factors; D055815:Young Adult
chemical_list: D007074:Immunoglobulin G