He then completed an internship and residency in pediatrics at the University of California, San Francisco, followed by a fellowship in infectious diseases at the University of Southern California Medical School and a residency in preventive medicine at the Centers for Disease Control and Prevention.
He then completed an internship and residency in pediatrics at the University of California, San Francisco, followed by a fellowship in infectious diseases at the University of Southern California Medical School. Orenstein then completed a residency in preventive medicine at the Centers for Disease Control and Prevention.