Changes and challenges for the practitioner.

Abstract

We continue to advance our knowledge regarding susceptible hosts. As people live longer, society is faced with a new problem of dealing with ever-increasing numbers of elderly with inadequate immune defense. HIV infections, cancer drugs, and steroids continue to add more persons to this pool. As we prepare to move into the twenty-first century, historical perspectives on our past triumphs and failures allow us to feel confident to meet the challenges ahead in preventing life-threatening illnesses in persons with immune deficiency.