[1] Univ North Carolina Chapel Hill, Gillings Sch Global Publ Hlth, Dept Epidemiol, 135 Dauer Dr, Chapel Hill, NC 27599 USA
[2] Univ N Carolina, Injury Prevent Res Ctr, Chapel Hill, NC USA
[3] Univ North Carolina Chapel Hill, Sch Med, Dept Pediat, Div Infect Dis, Chapel Hill, NC 27599 USA
[4] Univ North Carolina Chapel Hill, Gillings Sch Global Publ Hlth, Chapel Hill, NC 27599 USA
[5] Univ N Carolina, Canc Informat & Populat Hlth Resource, Lineberger Canc Ctr, Chapel Hill, NC USA
[6] Univ Nebraska Med Ctr, Coll Allied Hlth Profess, Omaha, NE USA