Children younger than 5 years old - particularly children younger than 2 years old, adults 65 years of age or older and pregnant women.
Persons with chronic diseases of the lung (including asthma), heart (except hypertension), kidney, liver, blood (including sickle cell disease), brain or nervous system, muscles (particularly those that cause difficulty with swallowing), or metabolism (including diabetes mellitus); immunosuppressant (weakened immune system) including that caused by medications or by HIV.
Persons younger than 19 years of age who are receiving long-term aspirin therapy because of an increased risk for Reye syndrome.