Fulminant H1N1 and severe acute respiratory syndrome coronavirus-2 infections with a 4-year interval without an identifiable underlying cause: a case report.

The patient experienced very similar severe clinical pictures triggered by H1N1 and severe acute respiratory syndrome coronavirus-2 infections, indicating an underlying inability to contain these infections. We were unable to show that the patient had any of the currently known types of immune incompetence but identified genetic changes possibly contributing to the severe course of both infections. Further analyses to delineate contribution factors are needed.