Effect of clinical and virological parameters on the level of neutralizing antibody against pandemic influenza A virus H1N1 2009.

Background: Little is known about the antibody response in natural infection by the novel 2009 influenza A (H1N1) virus and its relationship with clinical and virological parameters. The relative lack of background neutralizing antibody against this novel virus provides a unique opportunity for understanding this issue.

Methods: Case patients presenting with influenza-like illness who were positive for the pandemic H1 gene by reverse transcription polymerase chain reaction were identified.