All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. Ruth Lynfield reports serving as an executive officer for the Council of State and Territorial Epidemiologists (CSTE), a former executive officer for the National Foundation for Infectious Diseases (NFID), an associate editor of and infectious diseases program committee member for the American Academy of Pediatrics (AAP), and receipt of travel support to attend meetings from CSTE, NFID, AAP, and the Infectious Diseases Society of America; a fee for work as an associate editor for the AAP Red Book was donated to the Minnesota Department of Health. Jennifer Zipprich reports that her spouse is employed by Pfizer. Tyler Winkelman reports support from the National Institutes of Health, the Minnesota Department of Health, and the Substance Abuse and Mental Health Services Administration, to Hennepin County and payment from the Louisiana Center for Children’s Rights for expert testimony. Elizabeth M. Dufort received consulting fees for service as a public health physician consultant with Hutton Health Consulting for a CSTE project related to congenital infections but not related to parvovirus. No other potential conflicts of interest were disclosed.