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

Children under oncological therapy are at risk of infection by hepatitis B virus (HBV).To determine the prevalence of infection of HBV in children with cancer who have undergone chemotherapy or have had a hematopoietic stem cell transplant.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 which a low volume of sample was available, only one marker was studied (HBsAg in two and anti HBc in three).Samples came from children aged 4 months to 18 years, 104 males (61%). They had 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 (1.8%) and anti HBc in ten (7%). In 5 patients that had negative HBsAg and positive anti HBc, anti surface antigen antibodies (anti HBs) were determined and resulted positive in four.The prevalence of HBV in this sample was 7% if both serologic markers are considered and 1.8% if only HBsAg is considered.