title: Addressing parents' concerns: do multiple vaccines overwhelm or weaken the infant's immune system?
abstract: Recent surveys found that an increasing number of parents are concerned that infants receive too many vaccines. Implicit in this concern is that the infant's immune system is inadequately developed to handle vaccines safely or that multiple vaccines may overwhelm the immune system. In this review, we will examine the following: 1) the ontogeny of the active immune response and the ability of neonates and young infants to respond to vaccines; 2) the theoretic capacity of an infant's immune system; 3) data that demonstrate that mild or moderate illness does not interfere with an infant's ability to generate protective immune responses to vaccines; 4) how infants respond to vaccines given in combination compared with the same vaccines given separately; 5) data showing that vaccinated children are not more likely to develop infections with other pathogens than unvaccinated children; and 6) the fact that infants actually encounter fewer antigens in vaccines today than they did 40 or 100 years ago.
authors.affiliation: Section of Infectious Diseases, Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, and Wistar Institute of Anatomy and Biology, Philadelphia, Pennsylvania, USA. offit@email.chop.edu
authors.forename: Paul A
authors.initials: PA
authors.lastname: Offit
authors.forename: Jessica
authors.initials: J
authors.lastname: Quarles
authors.forename: Michael A
authors.initials: MA
authors.lastname: Gerber
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Hackett
authors.forename: Edgar K
authors.initials: EK
authors.lastname: Marcuse
authors.forename: Tobias R
authors.initials: TR
authors.lastname: Kollman
authors.forename: Bruce G
authors.initials: BG
authors.lastname: Gellin
authors.forename: Sarah
authors.initials: S
authors.lastname: Landry
mesh_terms: D000328:Adult; D001402:B-Lymphocytes / Q000276:immunology; D004198:Disease Susceptibility / Q000276:immunology; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D007112:Immunity, Maternally-Acquired / Q000276:immunology; D007153:Immunologic Deficiency Syndromes / Q000276:immunology; D007223:Infant; D007231:Infant, Newborn; D010290:Parents; D017778:Vaccines, Combined / Q000009:adverse effects / Q000276:immunology*
chemical_list: D017778:Vaccines, Combined