title: Challenges in the development of combination vaccines.
authors.affiliation: Department of Virus and Cell Biology, Merck Research Laboratories, West Point, Pennsylvania 19486, USA.
authors.forename: R W
authors.initials: RW
authors.lastname: Ellis
mesh_terms: D000917:Antibody Formation; D001428:Bacterial Vaccines; D002648:Child; D002675:Child, Preschool; D015721:Diphtheria-Tetanus-Pertussis Vaccine; D006801:Humans; D007115:Immunization Schedule; D007223:Infant; D017778:Vaccines, Combined; D014765:Viral Vaccines
chemical_list: D001428:Bacterial Vaccines; D015721:Diphtheria-Tetanus-Pertussis Vaccine; D017778:Vaccines, Combined; D014765:Viral Vaccines