Three cases of simultaneous seroconversion to hepatitis C virus (HCV) in a hemodialysis unit initiated the investigation of the viral strains of 14 seropositive patients in the unit by nucleotide sequencing. The results showed that five patients had been infected with the same viral strain, and indicated that two other patients were sharing a second strain. Transmission was not related to blood transfusions and not associated with the dialysis machines, but occurred between patients treated on the same shift. The number of cases was higher than expected from the serological data. Thus, spread of virus may occur at high frequencies in environments where parenteral routes are made accessible, in spite of rigorous preventive measures. This may raise concern that non-transfusion associated spread of HCV may be present and unnoticed in several hospital settings.

ABSTRACT. Objective. To evaluate viral vaccination immunity and booster responses in children treated successfully for acute lymphoblastic leukemia by chemotherapy and to study the response to treatment of antibody-producing plasma cells that are important for persistence of humoral immunity.Methods. Forty-three children who were in continuous first remission for a median of 5 years (range: 2-12 years) were studied. Before the leukemia was diagnosed, all children had been immunized against measles, mumps, and rubella according to the Swedish National immunization program. We analyzed levels of serum antibodies against measles and rubella by enzyme immunoassays. Avidity tests for measles antibodies were concomitantly performed by enzyme-linked immunosorbent assay for measles virus immunoglobulin G detection. The proportion of plasma cells in bone marrow was studied by flow cytometry at different times during treatment and follow-up. Children who lacked protective levels of antibodies to vaccination antigens were reimmunized. Serum was collected 3 months after immunization to assess vaccination responses.Results. After completion of the treatment, only 26 of the 43 children (60%) were found to be immune against measles and 31 (72%) against rubella. The proportion of bone marrow plasma cells decreased during treatment but returned to normal after 6 months. Revaccination caused both primary and secondary immune responses. Six of the 14 children without immunity failed to achieve protective levels of specific antibodies against measles and 3 against rubella.Conclusions. Our finding of loss of antibodies against measles and rubella in children treated with intensive chemotherapy suggests that reimmunization of these patients is necessary after completion of the treatment. To determine reimmunization schedules for children treated with chemotherapy, vaccination responses need to be studied further. A n increasing number of children survive leukemia as a result of improved and more intense chemotherapy. Other factors that influence outcome are improved supportive care including platelet transfusions, treatment with growth factors such as granulocyte colony-stimulating factor, and prophylactic antibiotic treatment. 1,2 Few studies have focused on potential long-term immunologic consequences of chemotherapy in survivors of childhood leukemia. Short-term (Ͻ2 years) effects of chemotherapy on immune function have previously been documented in children who were treated for malignancies, including acute lymphoblastic leukemia (ALL). 3,4 In those children, severe Band T-cell depletion results in clinical complications related to immune incompetence, 5,6 although the total B-and T-cell counts resolve quantitatively 6 months to 1 year after cessation of therapy. [7][8][9][10] In earlier studies, children who were treated with chemotherapy had lower levels of antibodies against common viral vaccination antigens such as measles, mumps, rubella, and polio. 11 The clinical implications, if any, of this finding are not completely und...

Acute respiratory tract infections are caused by a large number of viruses. Diagnostic methods have until recently been available only for a limited number of these viruses. With the objective to achieve sensitive assays for all respiratory viruses, a rational workflow in the laboratory, and a short turn-around time, a real-time PCR diagnostic platform for daily rapid detection of 15 respiratory viruses was developed. The system was evaluated on 585 stored nasopharyngeal aspirates from hospitalized children. Previous analysis by immunofluorescence and virus isolation identified viruses in 37% of the samples while the new PCR diagnostic panel detected 57% virus positive samples. The new platform was introduced in the laboratory in October 2007 and has then fully replaced the standard immunofluorescence assay for rapid detection of viruses and virus isolation.