Kliniske undersøgelser viser imidlertid, at når HEXAVAX blev indgivet samtidigt med PREVENAR (konjugeret saccharid pneumokokvaccine, adsorberet) var frekvensen af reaktioner med feber højere end det, der ses efter indgift af hexavalente vacciner alene.
However when HEXAVAC was co-administered with PREVENAR (pneumococcal polysaccharide conjugated vaccine, adsorbed) in clinical studies, the rate of febrile reactions was higher compared to that occurring following the administration of hexavalent vaccines alone.