Scientific Publications by FDA Staff

Transfusion 2006 Sep;46(9):1589-92

Absence of detectable viremia in plasma and peripheral blood mononuclear cells from smallpox vaccinees: implications for blood safety.

Srinivasan K, Akolkar PN, Taffs RE, Hewlett IK

Srinivasan K, DETTD, CBER, FDA, HFM 315,Lab Mol Virol, 1401 Rockville Pike, Rockville, MD 20852 USA DETTD, CBER, FDA, HFM 315,Lab Mol Virol, Rockville, MD 20852 USA US FDA, Lab Bacterial Parasit & Unconvent Agents, OBRR, CBER, Rockville, MD 20857 USA

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. STUDY DESIGN AND 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. CONCLUSION: 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.