title: Absence of detectable viremia in plasma and peripheral blood mononuclear cells from smallpox vaccinees: implications for blood safety.
abstract: BACKGROUND
  Mass smallpox vaccination with live vaccinia virus has been considered as a preventive measure to counter bioterrorism involving smallpox. This has raised concerns about the possibility of vaccinia virus being transmitted from vaccinated blood donors to recipients. The results of this study could be used to define an appropriate deferral period for blood donors (vaccinated against smallpox) to ensure safety of the blood supply.
  
  
  METHODS
  A procedure was developed to culture vaccinia virus from plasma and peripheral blood mononuclear cells (PBMNCs) of vaccinees enrolled in three smallpox vaccine clinical trials. A total of 665 plasma and PBMNC samples were obtained from 95 vaccinated subjects.
  
  
  RESULTS
  Vaccinia viremia was not detected by virus culture from plasma and PBMNC samples of healthy vaccinees 3 to 56 days after vaccination under our assay conditions. Plasma viremia assay had a sensitivity of approximately 66 plaque-forming units per mL with a Vero cell culture assay.
  
  
  CONCLUSIONS
  The results of this study present evidence that in the case of mass vaccination, the risk of transmission of vaccinia virus by blood transfusion would likely be low.
authors.affiliation: Laboratory of Molecular Virology, Division of Emerging and Transmission Transmitted Diseases, CBER, Food and Drug Administration, Rockville, Maryland 20852-1448, USA. kumar.srinivasan@fda.hhs.gov
authors.forename: Kumar
authors.initials: K
authors.lastname: Srinivasan
authors.forename: Pradip N
authors.initials: PN
authors.lastname: Akolkar
authors.forename: Rolf E
authors.initials: RE
authors.lastname: Taffs
authors.forename: Indira K
authors.initials: IK
authors.lastname: Hewlett
mesh_terms: D000818:Animals; D023482:Bioterrorism; D018929:Cell Culture Techniques; D002522:Chlorocebus aethiops; D002986:Clinical Trials as Topic; D000075202:Contraindications; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000166:cytology*; D032541:Mass Vaccination; D012449:Safety; D012899:Smallpox / Q000517:prevention & control* / Q000635:transmission; D012900:Smallpox Vaccine / Q000008:administration & dosage* / Q000009:adverse effects; D014611:Vaccination / Q000592:standards*; D014616:Vaccinia virus / Q000302:isolation & purification; D014709:Vero Cells; D014766:Viremia / Q000139:chemically induced
chemical_list: D012900:Smallpox Vaccine