[1] Vanderbilt Univ, Med Ctr, Dept Med, Nashville, TN USA
[2] Vanderbilt Univ, Med Ctr, Dept Pediat, Nashville, TN 37232 USA
[3] Vanderbilt Univ, Med Ctr, Dept Microbiol, Nashville, TN 37232 USA
[4] Vanderbilt Univ, Med Ctr, Dept Immunol, Nashville, TN 37232 USA
[5] Vanderbilt Univ, Med Ctr, Dept Prevent Med, Nashville, TN 37232 USA
[6] Vanderbilt Univ, Med Ctr, Dept Biostat, Nashville, TN 37232 USA
[7] Univ Rochester, Sch Med & Dent, Dept Pediat, Rochester, NY 14642 USA
[8] Ctr Dis Control & Prevent, Natl Ctr Infect Dis, Atlanta, GA USA