title: Bridging the gap-a reply.
authors.forename: L
authors.initials: L
authors.lastname: Hayflick
authors.forename: S
authors.initials: S
authors.lastname: Plotkin
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000209:etiology*; D000350:Africa, Central; D000818:Animals; D002460:Cell Line; D002648:Child; D002675:Child, Preschool; D003470:Culture Media; D004171:Diploidy; D006801:Humans; D007223:Infant; D017955:Poliovirus / Q000276:immunology*; D011055:Poliovirus Vaccine, Oral / Q000008:administration & dosage; D014481:United States; D014765:Viral Vaccines / Q000009:adverse effects*
chemical_list: D003470:Culture Media; D011055:Poliovirus Vaccine, Oral; D014765:Viral Vaccines