1. Department of Family Medicine, University of Pittsburgh , Pittsburgh, Pennsylvania , USA
2. National Center Immunizations and Respiratory Disease, Center for Disease Control and Prevention , Atlanta, Georgia , USA
3. Department of Immunology, University of Pittsburgh , Pittsburgh, Pennsylvania , USA
4. Department of Pediatrics, University of Pittsburgh , Pittsburgh, Pennsylvania , USA
5. Falk Pharmacy, University of Pittsburgh Medical Center (UPMC) , Pittsburgh, Pennsylvania , USA