Efficacy
Infanrix hexa was highly immunogenic for the vaccine antigens diphtheria and tetanus toxoids, poliovirus type 1, 2 and 3 antigens, pertussis antigens (PT, FHA and PRN), HBsAg and the Hib antigen (polyribosylribitol phosphate [PRP]) both as primary and booster vaccination in healthy infants aged < 2 years, with antibodies against these antigens persisting in the long term.6
Omenaca et al reviewed outcomes of GSK's hexavalent vaccine Infanrix hexa (DTPa-HBV-IPV/Hib) in 10 clinical studies in preterm infants up to 24 weeks gestation. They showed that up to 92.5% of these infants were seropositive to all vaccine antigens after 3-dose primary vaccination (98.7% for diphtheria and tetanus; 100% for polio serotypes
1 and 2, 90.9% for type 3 and 92.4% for pertussis, 92.5% for Hib).7
Several studies on response to pertussis and Hib vaccine in preterm infants have shown decreased immunogenicity as compared to term infants. However, despite the difference, the antibody levels against the different antigens were still
higher than what is considered as a protective level.8
With regard to hepatitis B vaccine, studies in preterm babies have shown variable effects,where some trials showing reduced seroconversion in babies <2000 g 9, while others showing adequate seroconversion by 30 days of age regardless of birth weight.10 Given the variable results, preterm babies <32 weeks are recommended to have a booster hepatitis B vaccine dose at 12months of age in babies with anti-Hbs titres <10 mIU/mL or unknown.
Infanrix hexa was administered concomitantly with a rotavirus vaccine (Rotarix) in a randomised, double-blind, placebo-controlled trial and with a 13-valent-pneumococcal vaccine (Prevenar-13) in several studies. Limited data from these studies suggest that co-administration of these vaccines with Infanrix hexa does not affect the immunogenicity of either co-administered vaccine.6
Infanrix hexa can be co-administered with other live or inactivated vaccines without interference on the immune response.11
Safety
In 2007 the Committee for Medicinal Products for Human Use reviewed cases of apnoea in preterm infants following vaccination and concluded that the apnoea occurred due to immaturity of the immune system. Hence, their recommendation to monitor very preterm infants for up to 48–72 hours after vaccination.11
Historical concerns about potential temporal association between sudden unexpected death (SUD) and hexavalent vaccines has been extensively investigated and in 2003 the European Medicines Agency concluded absence of a cause-effect relationship and no change in the benefit-risk profile of then available hexavalent vaccines.7
Available clinical data from more than 10 years’ experience with the vaccine suggest that Infanrix hexa as primary and booster vaccination is a safe and useful option for providing protection against the common childhood diseases of diphtheria, tetanus, poliomyelitis, pertussis, hepatitis B and invasive Hib disease.6
Infanrix hexa was generally well tolerated as primary and booster vaccination in infants aged < 2 years, with most adverse local and general symptoms being mild to moderate in intensity.12
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