1. From the Epidemic Intelligence Service (M.L.H.), the National Center for Immunizations and Respiratory Diseases (A.C., L.F., A.P.), the Division of Viral Diseases (S.I.G., L.K., S.T., X.L., S. Lindstrom, M.A.P., W.C.W., H.M.B.), the Influenza Division (T.M.U.), and the Division of Preparedness and Emerging Infections (S.K.P.), Centers for Disease Control and Prevention, Atlanta; and the Washington State Department of Health, Shoreline (M.L.H., C.D., S. Lindquist, K.H.L., J.W.), Snohomish Health District ...