Respiratory Syncytial Virus (RSV) Infections in Immunocompromized Children.

Eleven children who were immunocompromized due to chemotherapy were infected with respiratory syncytial virus (RSV) during an outbreak of RSV infection in the Pediatric Oncology Unit of Queen Mary Hospital, The University of Hong Kong. The clinical symptoms, effect on treatment regimen, outcome of infection and viral clearance had been followed prospectively in all 11 children. Viral clearance was documented by immunofluorescence and PCR studies of nasopharyngeal aspirates or nasal/throat swabs. Eight of the 11 children had upper respiratory symptoms with the remaining 3 patients progressing to lower respiratory tract infections (LRTI). All except one had protracted viral symptoms but eventually recovered without the need for specific anti-viral treatment or intensive support. However, the chemotherapy regimen or scheduled BMT had been significantly interrupted. One patient developed progressively severe pneumonia which was further complicated by adenovirus reactivation causing bone marrow failure and severe sepsis resulting in death of this patient. The viral clearance of RSV was delayed in all patients with median of 20 days (range 9–81 days). One patient had recurrence of RSV detected by PCR 35 days after intial documentation of clearance, after a BMT procedure. The delayed viral clearance correlated with protracted viral symptoms. In conclusion, RSV clearance is delayed in immunocompromized hosts causing protracted viral symptoms, progression to LRTI and interruption to chemotherapy treatment. The delay in viral clearance appears proportional to the degree of immunosuppression of the individual.