One infant in the Neonatal Intensive Care Unit (NICU) at St. Louis Children's Hospital experienced respiratory decompensation and tested positive for influenza virus type A by fluorsescent antibody stain performed on a nasopharyngeal swab. This infant received treatment doses of oseltamivir. Subsequently, 27 other infants received oseltamivir prophylaxis for exposure to influenza virus type A. Exposed infants were those who shared a primary medical team, nursing care, respiratory therapist, physical therapist, or occupational therapist with the influenza A positive infant. Prophylaxis was deemed necessary by the attending neonatologist after consultation with the Infectious Diseases Division of the Department of Pediatrics at the Washington University School of Medicine.