The present invention relates to the field of methods of testing a vaccine response in an animal model to obtain information on the response of humans to the same vaccinogen. The present invention provides a method of determining the dose response of a human to a polysaccharide conjugate vaccine comprising an immunogenic carrier protein and a bacterial polysaccharide, said method comprising the steps of administering to an infant animal a dose amount of said conjugated vaccine, and determining the immune response of the animal to the bacterial polysaccharide as a measure of the immune response of a human. Preferred, modes of administration of vaccine in the model, dose of vaccine tested, time between doses, time of serum harvesting, method of determination of immune response, and type (and age) of infant animal used are also all provided.