Influenza A prophylaxis with amantadine in a boarding school.

In a boarding school for boys, where routine influenza vaccination is carried out annually, 267 boys were given amantadine (100 mg daily) and 269 received no specific treatment during an influenza A (H1N1) outbreak. 3 boys receiving amantadine and 29 boys receiving no medication had laboratory-proven influenza A. There are circumstances when the prophylactic use of amantadine may be justified for the control of influenza A outbreaks in boarding schools and other institutions where high attack-rates are experienced.