Influenza can cause significant mortality either by producing a severe viral pneumonia or by permitting bacteria like Staphylococcus aureus or Streptococcus pneumoniae to infect the lung. In milder cases of influenza, there may be significant time lost from work or school.

Note that influenza can cause severe disease in persons of any age, and the current CDC recommendation is for annual vaccination of all persons older than 6 months. Nevertheless, the risk of severe, and perhaps fatal, influenza is greater in certain groups of individuals. Which patient groups listed below should be especially encouraged to take the vaccine annually and as early as possible (more than one is correct)?

Click arrow to advance