Oseltamivir prophylaxis during the influenza season in a paediatric cancer centre: prospective observational study.

Objective: To determine the role of oseltamivir prophylaxis for immunocompromised patients.
Design: Prospective, non-blinded, non-controlled observational study.
Setting: A paediatric cancer centre, Hong Kong.
Participants: Thirty-two patients, immunocompromised by chemotherapy or bone marrow transplantation during an influenza season in 2001.
Intervention: Oral oseltamivir prophylaxis 75 mg/d for 8 weeks.
Main Outcome Measures: Laboratory-confirmed influenza infection, symptoms of influenza, drug compliance, and any side-effects from oseltamivir treatment. Laboratory monitoring included virological surveillance for influenza A and B, blood counts, and renal and liver function tests.
Results: Patients' median age was 14.3 years (range, 6.3-23.4 years). Underlying conditions included malignancy (n=29) and other haematological diseases (n=3). No documented influenza infection according to serological tests was present throughout the study period. Five patients with symptoms of upper respiratory tract infection did not have any influenza infection detected by rapid virological assay and viral culture. For 16% of patients, the main side-effect in the study was gastro-intestinal upset.
Conclusions: Oral oseltamivir 75 mg once daily for 8 weeks may be useful in the prevention of influenza infection in patients immunocompromised by chemoradiotherapy; side-effects are few and acceptable.