Evaluation of risk factors associated with diminished immune response to Haemophilus influenzae type b PRP-D vaccine among Inuit infants of the Northwest Territories.

Haemophilus influenzae type b (Hib) is the most important cause of serious invasive bacterial disease in young children in many countries, particularly industrialized countries. A 1986 study using PRP-D vaccine among Aboriginal infants in the Northwest Territories (N.W.T.) reported that all ethnic groups responded poorly, but the proportion of Inuit (44%) who responded with protective anti-PRP antibody levels of $\geq0.15\ \mu$/mL was smaller than that of the Dene (60%). This study was undertaken to explore possible reasons for the poorer results of the Inuit infants. Results. The results suggested that the difference between two vaccine lots and sex, and possibly age and region, were implicated in the difference between the groups. Conclusions. The research did not entirely achieve a resolution of the part which ethnicity and other factors played in Inuit response to PRP-D vaccine. The importance of the study, however, was that, by examining the data in more detail, factors other than ethnicity were identified as potentially having an effect on the poor immune response of the Inuit infants in the 1986 N.W.T. study. (Abstract shortened by UMI.