On Jun. 24, 2008, the FDA licensed a combined diphtheria and tetanus toxoid and acellular pertussis (DTaP) and inactivated poliovirus (IPV) vaccine, DTaP-IPV (KINRIX, GlaxoSmithKline Biologicals, King of Prussia, Pa.). KINRIX was licensed for use as the fifth dose of DTaP and the fourth dose of IPV in children 4 through 6 years of age whose previous DTaP vaccine doses were with INFANRIX (DTaP) or PEDIARIX (DTaP-HepB-IPV) or both