Combination diphtheria-tetanus-5 component acellular pertussis-inactivated poliovirus-Haemophilus influenzae b conjugate-hepatitis B vaccine ( DTaP5-IPV-Hib-HepB ) administered either concurrently with 7-valent pneumococcal conjugate vaccine ( PCV7 ) or 1 month apart was generally safe and immunogenic at 2 , 4 and 6 months of age .