[1] Chosun Univ, Sch Med, Dept Prevent Med, Kwangju 501759, South Korea
[2] Chosun Univ, Coll Med, Dept Internal Med, Div Infect Dis, Kwangju, South Korea
[3] Chungnam Natl Univ, Sch Med, Dept Prevent Med, Taejon, South Korea
[4] Seonam Univ, Coll Med, Dept Prevent Med, Kwangju, South Korea
[5] Korea Ctr Dis Control & Prevent, Kwangju, South Korea