Vaccine-preventable outbreaks: still with us after all these years.

Outbreaks of vaccine-preventable diseases continue to occur in the United States, and they have been occurring at increasing rates over the past decade. Factors contributing to these outbreaks include importation from abroad, under-vaccination of segments of the population, and incomplete protection or waning immunity with certain vaccines. This article reviews recent outbreaks of measles, mumps, and pertussis in the United States to highlight the extent to which outbreaks of these vaccine-preventable diseases are still occurring and even increasing. Appreciating the magnitude of these illnesses may help the physician in educating families who are hesitant about vaccines.