Seroprevalence of hepatitis B virus and hepatitis C virus in Monte Negro in the Brazilian western Amazon region Soroprevalência de hepatite B e hepatite C em Monte Negro, Rondônia, Região Amazônica Ocidental Brasileira

PURPOSE: This study was carried out in Monte Negro (state of Rondônia), a village in the Brazilian western Amazon region, where a University of São Paulo Medical School program for medical student training in rural assistance took place. It aimed to determine the prevalence of hepatitis B virus and hepatitis C virus, to investigate risk factors for infection, and to evaluate the State immunization program against hepatitis B virus in the region. METHODS: The study is a cross-sectional seroprevalence survey, comprising 267 volunteers who answered a comprehensive questionnaire and had blood samples collected, which were analyzed in São Paulo for the presence of antibodies against hepatitis B virus (Hbs Ag, anti-Hbs, and anti-Hbc) and hepatitis C virus using commercial kits. Data were stored in a specific data bank, and the association between seropositivity and potential risk factors was analyzed by means of uni-, bi-, and multi-variate analysis, considering ±5%. RESULTS: The seroprevalence of hepatitis B virus was 61.79% and of hepatitis C virus was 0.38%. Statistical analysis on the data bank showed that the prevalence of hepatitis B virus rose significantly with age, especially after adolescence. Infection was higher in those coming from outside the state of Rondônia. Exposure to vaccination against hepatitis B virus was higher in younger individuals and in those who were born in Rondônia. CONCLUSION: Monte Negro is a highly endemic region for hepatitis B virus but not for hepatitis C virus. Our results also provide indirect evidence indicating a significant improvement in the immunization program in Rondônia in recent years.OBJETIVOS: O presente estudo foi realizado em Monte Negro, Rondônia, Amazônia Oriental, onde um projeto de acadêmicos de Medicina da Universidade de São Paulo promoveu assistência médica à população rural. O objetivo foi determinar a soroprevalência de Hepatite B e Hepatite C, investigar os fatores de risco para sua infecção e avaliar o status imunológico vacinal contra Hepatite B nesta região. MÉTODOS: O estudo é uma pesquisa de corte transversal de soroprevalência, compreendendo 267 voluntários que tiveram suas amostras sanguíneas coletadas após preenchimento de um questionário. As amostras foram analisadas em São Paulo usando kits comerciais pesquisando anticorpos contra Hepatite B (AgHBs, Anti-HBs e Anti-HBc) e Hepatite C . Um banco de dados montado através do questionário foi analisado em relação aos resultados sorológicos com te