Haemophilus influenzae type b infections: secondary cases and recurrent disease

Invasive Haemophilus influenzae type b infections in Denmark have not been known to lead to secondary cases, and recurrent disease has not been observed. Three case histories are presented and the literature reviewed. Secondary disease occurs more often among household contacts than among day-care contacts, which probably is due to genetic factors. The same factors might also influence the risk of contracting recurrent disease. Parents should be informed of the risk and promptly have their children medically evaluated in case of febrile illness. Epidemiological data from Denmark, however, do not provide background for the recommendation of rifampicinprophylaxis to patients with Hib-infection or their contacts.