Vaccines are one of the most successful public health interventions of the past century, says Doug Campos-Outcalt, MD. He discusses vaccine safety and adverse reactions, and he stresses the dangers of contracting an infection that can be prevented by vaccination. Campos-Outcalt is a senior lecturer at the University of Arizona's Mel and Enid Zuckerman College of Public Health and a clinical professor at the University of Arizona's College of Medicine in Phoenix. He was visiting Upstate to give a lecture about basing clinical and public health recommendations on sound scientific evidence.