Rifampin Prophylaxis v Placebo for Household Contacts of Children With Hemophilus influenzae Type b Disease

The efficacy of rifampin prophylaxis (20 mg/kg/day in two doses for four days) in eliminating pharyngeal Hemophilus influenzae type b from household contacts of 38 patients with invasive Hemophilus disease was evaluated in a prospective, placebo-controlled fashion. At the end of treatment, rifampin efficacy was 91% in subjects younger than 5 years of age and 100% in those subjects older than 5 years. The H influenzae type b carrier rate of rifampin-treated subjects was significantly smaller than that of placebo-treated subjects one month after prophylaxis. However, 22% to 25% of rifampin-treated carriers younger than 5 years of age were colonized with H influenzae type b, based on cultures obtained one to four weeks after prophylaxis, while approximately 75% of placebo-treated carriers were still positive at this time.