title: Sexual activity and hepatitis B and C virus infection among young adults after introduction of a vaccination program in an area of high endemicity.
abstract: BACKGROUND
  In areas where hepatitis is endemic, little is known about the sexual transmission of HBV after introduction of an HBV vaccination program.
  
  
  METHODS
  We used a self-administered questionnaire and serological tests for HBsAg, anti-HBs, anti-HBc, and anti-HCV to examine the role of sexual activity, as well as sociodemographic status, lifestyle habits, and a history of vaccinations, transfusions, and surgery, in the transmission of HBV and HCV in Korea. The subjects were 865 female and 541 male university students (median age, 19 years; age range, 16-25).
  
  
  RESULTS
  Overall seropositivity was 8.1% for HBsAg, 69.3% for anti-HBs, 21.3% for anti-HBc, and 0.4% for anti-HCV. Regarding HBV, 8% of the subjects were chronic carriers or had recently been infected, 22.8% were never exposed and nonvaccinated, 16.6% were exposed noncarriers, and 52.7% had most likely been vaccinated. We found a significant association between HBsAg seropositivity and history of sexual intercourse (Odds Ratio, 1.8; 95% CI, 1.1-2.8). Students without serologic evidence of immunization against HBV were more likely to have become HBsAg-positive after becoming sexually active.
  
  
  CONCLUSIONS
  Our findings suggest that sexual transmission does occur among adolescents and young adults who have not been vaccinated, whereas vaccination protects individuals from becoming an HBV carrier after becoming sexually active.
authors: National Cancer Control Research Institute, National Cancer Center, Goyang, Republic of Korea.
authors: Min Kyung
authors: MK
authors: Lim
authors: Silvia
authors: S
authors: Franceschi
authors: Salvatore
authors: S
authors: Vaccarella
authors: Young-Hee
authors: YH
authors: Ju
authors: Jin-Kyoung
authors: JK
authors: Oh
authors: Hyun-Joo
authors: HJ
authors: Kong
authors: Dong-Il
authors: DI
authors: Kim
authors: Byoung-Gwon
authors: BG
authors: Kim
authors: Jung-Il
authors: JI
authors: Kim
authors: Kap-Yeol
authors: KY
authors: Jung
authors: Dong-Soon
authors: DS
authors: Lee
authors: Hai-Rim
authors: HR
authors: Shin
mesh_terms: D000293:Adolescent; D005260:Female; D006509:Hepatitis B / Q000453:epidemiology / Q000517:prevention & control / Q000635:transmission*; D006510:Hepatitis B Antibodies / Q000097:blood; D006514:Hepatitis B Surface Antigens / Q000097:blood; D006526:Hepatitis C / Q000453:epidemiology / Q000517:prevention & control / Q000635:transmission*; D006801:Humans; D007723:Korea / Q000453:epidemiology; D008019:Life Style; D008297:Male; D032541:Mass Vaccination; D012725:Sexual Behavior / Q000706:statistics & numerical data*; D015229:Sexually Transmitted Diseases, Viral / Q000453:epidemiology; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires; D014761:Viral Hepatitis Vaccines; D055815:Young Adult
chemical_list: D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens; D014761:Viral Hepatitis Vaccines