Nosocomial swine influenza (H1N1) pneumonia: lessons learned from an illustrative case.

In the spring of 2009, our institution found itself at the epicentre of the "herald wave" of the swine influenza (H1N1) pandemic in New York. We were inundated with hundreds of patients exhibiting influenza-like illnesses (ILIs), presenting for rapid influenza A testing. During this pandemic, an infant with newly diagnosed acute lymphatic leukaemia (ALL) was admitted for induction chemotherapy. After being in hospital for a week, she developed high fever and shortness of breath, although her chest X-ray was clear. She was admitted to the paediatric intensive care unit (PICU) for mechanical ventilation. As we were in the midst of the pandemic, diagnosis of H1N1 pneumonia was considered and reverse transcription-polymerase chain reaction for H1N1 was positive. Contact investigation revealed that none of her family members/visitors had been in recent/close contact with anyone with ILI/H1N1. The investigation also revealed that paediatric healthcare staff, in contact with H1N1 patients, had rotated into PICU to care for the patient. Although no specific individual could be identified, it seems likely that H1N1 was transmitted to the patient by a healthcare worker who worked both in the paediatric ward and the PICU. This is the first known case of nosocomial paediatric transmission of H1N1 pneumonia.