Combination vaccines have advantages compared with single-antigen formulations—for instance, they require fewer injections and patient visits and potentially lower costs.

As many countries begin to include inactivated polio vaccine (IPV) in routine vaccination programmes, the use of high-valency combination vaccines is increasing (including the hexavalent diphtheria, tetanus, and acellular pertussis–hepatitis B virus–IPV/Haemophilus influenzae type b disease vaccine [DTPa-HBV-IPV/Hib]).

Combination vaccines are generally licensed on the basis of immunogenicity data, but these data can be inconclusive, and the interpretation of differing antibody titre responses to different products can be challenging.