Rifampin prophylaxis (20 mg/kg once daily for four days) was used in close contacts of children with Haemophilus influenzae type b (HIB) disease. Two hours after a dose, the concentration of rifampin in serum and saliva exceeded the minimum bactericidal concentrations of organisms obtained from four of the carriers. In both a randomized prospective and an open study, nasopharyngeal carriage was eradicated in 37 (95%) of 39 contacts. No cases of serious H influenzae disease occurred in four to six months of follow-up. At the dose and treatment schedule used, rifampin was safe and effective for eradication of HIB carriage.
Cox F, Trincher R, Rissing JP, Patton M, McCracken GH, Granoff DM. Rifampin Prophylaxis for Contacts of Haemophilus influenzae Type b Disease. JAMA. 1981;245(10):1043-1045. doi:10.1001/jama.1981.03310350031018