Children with cancer or stem cell transplantation (SCT) are at considerable risk to develop life threatening viral infections. Due to both underlying disease and immunosuppressive therapy lymphocyte number and function are low and the cellular immunity against viral infections is restricted or missing. As immunosuppressive treatment regimens and mismatched or T-cell-depleted stem cell products are being used increasingly, viral infections will become an even greater problem in the future. PCR-based methods have become an indispensable tool for early recognition, preemptive therapy, and monitoring therapeutic responses by qualitative and quantitative approaches. Assays are now available that allow for parallel screening of the 16 most common viral agents. Responses to antiviral therapy are often limited in immunocompromised patients and mainly depend on the time of their initiation. Most antiviral agents have a toxicity profile that may become clinically relevant and curtail antiviral therapy. New options for treatment are therefore warranted. For the next future, these may include the transfer of specific T-cells and other immunotherapeutic approaches. This article provides the recommendations of the Infectious Diseases Working Party of the German Society for Pediatric Hematology/Oncology (GPOH) and the German Society for Pediatric Infectious Diseases (DGPI) for diagnosis and treatment of viral infections in children with cancer or post HSCT. They are based on the results of clinical trials, case series and expert opinions using the evidence criteria set forth by the Infectious Diseases Society of America (IDSA).
