O'Callaghan Kevin P, Blatz Allison M, Offit Paul A
Division of Infectious Diseases, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.
Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia.
JAMA. 2020 Aug 4;324(5):437-438. doi: 10.1001/jama.2020.12190.