Seroprevalence of hepatitis B virus in children with cancer under chemotherapy in 6 hospitals of Santiago, Chile

Background: Children under oncological therapy are at risk of infection by hepatitis B virus (HBV). Aim: To determine the prevalence of infection of HBV in children with cancer who have undergone chemotherapy or have had an hematopoietic stein cell transplant. Material and methods: Collaborative, multi-centric study. Serum samples were collected from 281 children with cancer and episodes of febrile neutropenia, from 6 hospitals belonging to the public health network in the Metropolitan Region, between June 2004 and August 2006. These samples were stored at -70 degrees C In September 2006 200 samples were randomly chosen and 170 analyzed to determine hepatitis B virus surface antigen, (HBsAg) and anticore total antibodies (anti HBc) by fluorescent ELISA (Enzyme Linked Immunosorbent Assay). In five cases in whom a low volume of sample was available, only one marker was studied (HBsAg in two and anti HBc in three). Results. Samples came from? children aged 4 months to 18 years, 104 males (61%). They bad received an average of 38 transfusions (range 3-107) from 65 donors (range 3-345). Twelve children were found positive for some marker of HBV: HBsAg in three 0.8%) and anti HBc in ten (7016). In 5 patients that bad negative HBsAg and positive anti HBc, anti surface antigen antibodies (anti HBs) were determined and resulted positive in four. Conclusions: The prevalence of HBV in this sample was 7% if both serologic markers are considered and 1.8% if only HBsAg is considered (Rev Med Chile 2009; 137: 906-11).