How a mild influenza B infection can kill: A case of pulmonary hemorrhage.

Viral influenza is a seasonal infection associated with significant morbidity and mortality. Rapidly fatal hemorrhagic pneumonia has been described in previously healthy individuals with β-hemolytic Streptococcus pneumoniae in a small series of patients, but it is not common in patients coinfected with influenza B and β-hemolytic Streptococcus, particularly since influenza B is considered less pathogenic than influenza A. However, despite being uncommon, this coinfection seems to be associated with high morbidity and mortality, particularly in healthy individuals.