RESUMEN
OBJECTIVES: The main objective was to evaluate HBV infection and occult HBV infection (OBI) cases in mentally ill patients based on serological and molecular profiles. MATERIAL AND METHODS: Serum samples of 333 long-stay mentally ill patients were tested for the prevalence of HBV markers by serological (ELISA) and molecular (PCR) assays. The PCR products were sequenced to determine viral genotypes. RESULTS: It was observed a global prevalence of 12.9% (43/333) for HBV infection markers, considering HBsAg and/or anti-HBc positivity. Fourteen samples tested positive for anti-HBs alone. All samples positive (n=57) for any HBV serological markers were tested for HBV-DNA and six were positive: HBsAg/anti-HBc (n=1), anti-HBc/anti-HBs (n=1), anti-HBs alone (n=1), and anti-HBc alone (n=3). The rate of OBI was 9.2% (5/54) from samples that were anti-HBc and/or anti-HBs positive. All sequenced samples were characterized as genotype A. CONCLUSION: The high rate of HBV infections found in this study suggests the possibility of HBV transmission due to risk factors displayed by some patients, and highlights the importance of vaccination of susceptible patients and the staff of that institution.