Influenza and Pneumocystis jirovecii pneumonia in an allogeneic hematopoietic stem cell transplantation recipient: Coinfection or superinfection?

Influenza infection and Pneumocystis jirovecii pneumonia ( PJP ) in hematopoietic stem cell transplant ( HSCT ) patients are well characterized; however, no dual infections have been reported in this patient population and little evidence of mechanisms of interaction between the two infections exists. We present a 53‐year‐old male allogeneic HSCT patient on immunosuppressive therapy for the treatment of graft versus host disease initially diagnosed with influenza A H3 and later PJP . Despite the development of acute respiratory distress syndrome, the patient was successfully treated with appropriate antimicrobial therapy and aggressive supportive care. This case demonstrates the necessity of maintaining a high index of suspicion for fungal (including PJP ) coinfection or superinfection in the setting of worsening influenza infection.