title: Prevalence, Risk Behaviors, and Virological Characteristics of Hepatitis B Virus Infection in a Group of Men Who Have Sex with Men in Brazil: Results from a Respondent-Driven Sampling Survey.
abstract: BACKGROUND
  Men who have sex with men (MSM) are at increased risk of exposure to hepatitis B virus (HBV) compared with the general population. This study aims to assess the epidemiological and virological characteristics of HBV infection in a sample of MSM in Brazil, where data are scarce.
  
  
  METHODS
  A cross-sectional study was conducted among MSM in the City of Goiânia, Central Brazil, from March to November 2014, using Respondent-Driven Sampling (RDS). After signing the consent form, participants were interviewed and a blood sample collected. All samples were tested for HBV serological markers and HBV DNA. HBV nucleotide sequence analysis was also performed.
  
  
  RESULTS
  A total of 522 MSM were recruited in the study. The prevalence of HBV infection (current or past [presence of anti-HBc marker]) was 15.4% (95% CI: 8.7-25.8) and the rate of HBsAg carriers was 0.6% (95% CI: 0.2-1.6). About 40% (95% CI: 32.3-48.8) of the participants had serological evidence of previous HBV vaccination (reactive for isolated anti-HBs). In addition, 44.3% (95% CI: 36.1-52.9) were seronegative for all HBV markers. Age over 25 years old, receptive anal intercourse, previous sex with women, and history of sexually transmitted infections (STIs) were factors associated with HBV infection. HBV DNA was detected only in HBsAg-positive individuals. HBV isolates were classified into genotype A (subgenotypes A1 and A2), and some mutations were identified throughout the genome. Therefore, occult HBV infection was not observed in the study population.
  
  
  CONCLUSIONS
  Public health strategies should be improved for the MSM population in order to prevent HBV and other STIs, as well as to provide appropriate management of patients with active infections.
authors: Institute of Tropical Pathology and Public Health, Federal University of Goiás, Goiânia, Goiás, Brazil.
authors: Marina P
authors: MP
authors: Oliveira
authors: Institute of Tropical Pathology and Public Health, Federal University of Goiás, Goiânia, Goiás, Brazil.
authors: Márcia A D
authors: MA
authors: Matos
authors: Institute of Tropical Pathology and Public Health, Federal University of Goiás, Goiânia, Goiás, Brazil.
authors: Ágabo M C
authors: ÁM
authors: Silva
authors: Faculty of Nursing, Federal University of Goiás, Goiânia, Goiás, Brazil.
authors: Carmen L R
authors: CL
authors: Lopes
authors: Faculty of Nursing, Federal University of Goiás, Goiânia, Goiás, Brazil.
authors: Sheila A
authors: SA
authors: Teles
authors: Faculty of Nursing, Federal University of Goiás, Goiânia, Goiás, Brazil.
authors: Marcos A
authors: MA
authors: Matos
authors: Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Rio de Janeiro, Brazil.
authors: Natália
authors: N
authors: Spitz
authors: Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Rio de Janeiro, Brazil.
authors: Natalia M
authors: NM
authors: Araujo
authors: Department of Community Health, Federal University of Ceará, Fortaleza, Ceará, Brazil.
authors: Rosa M S
authors: RM
authors: Mota
authors: Department of Community Health, Federal University of Ceará, Fortaleza, Ceará, Brazil.
authors: Ligia R F S
authors: LR
authors: Kerr
authors: Institute of Tropical Pathology and Public Health, Federal University of Goiás, Goiânia, Goiás, Brazil.
authors: Regina M B
authors: RM
authors: Martins
mesh_terms: D000328:Adult; D001938:Brazil / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D006306:Health Surveys; D006509:Hepatitis B / Q000453:epidemiology* / Q000821:virology; D006514:Hepatitis B Surface Antigens / Q000097:blood; D006515:Hepatitis B virus / Q000235:genetics* / Q000302:isolation & purification; D018451:Homosexuality, Male / Q000523:psychology; D006801:Humans; D008297:Male; D010802:Phylogeny; D012309:Risk-Taking; D012725:Sexual Behavior
chemical_list: D006514:Hepatitis B Surface Antigens