Transfusion-related transmission of yellow fever vaccine virus--California, 2009.

In the United States, yellow fever (YF) vaccination is recommended for travelers and active duty military members visiting endemic areas of sub-Saharan Africa and Central/South America. The American Red Cross recommends that recipients of YF vaccine defer blood product donation for 2 weeks because of the theoretical risk for transmission from a viremic donor. On April 10, 2009, a hospital blood bank supervisor learned that, on March 27, blood products had been collected from 89 U.S. active duty trainees who had received YF vaccine 4 days before donation. This report summarizes the subsequent investigation by the hospital and CDC to identify lapses in donor deferral and to determine whether transfusion-related transmission of YF vaccine virus occurred. The investigation found that a recent change in the timing of trainee vaccination had occurred and that vaccinees had not reported recent YF vaccination status at time of donation. Despite a prompt recall, six units of blood products were transfused into five patients. No clinical evidence or laboratory abnormalities consistent with a serious adverse reaction were identified in four recipients within the first month after transfusion; the fifth patient, who had prostate cancer and end-stage, transfusion-dependent, B-cell lymphoma, died while in hospice care. Three of the four surviving patients had evidence of serologic response to YF vaccine virus. This report provides evidence that transfusion-related transmission of YF vaccine virus can occur and underscores the need for careful screening and deferral of recently vaccinated blood donors.