A review of the data from a trial sponsored by the Centers for Disease Control to evaluate the effectiveness of rifampin for the prevention of secondary cases of invasive Haemophilus influenzae type b disease and the recognition of failure of rifampin prophylaxis in some day care centers and families prompted the changed recommendations listed below. An increased risk of invasive H influenzae type b disease in household contacts, particularly in those less than 49 months of age had been demonstrated. Although nursery school and day care center contacts may also be at increased risk of secondary disease, the magnitude of this is uncertain at this time. Preliminary data from ongoing studies suggest that the risk of secondary disease among nursery school contacts may vary widely between centers. Asymptomatic colonization with H influenzae type b is frequent in household contacts of all ages. Rifampin, 20 mg/kg (600 mg maximum dose) given once daily for four days, eradicates H influenzae type b in approximately 95% of carriers.
In the trial conducted by the Centers for Disease Control, household and day care center contacts were randomized to receive rifampin prophylaxis or placebo. There was a significant diminution in secondary cases among rifampin recipients if the treated household and day care centers were combined. Four secondary cases occurred among the 800 placebo-treated contacts in contrast to no cases among the 1,166 rifampin-treated contacts (P = .03). Analysis of attack rates among children less than 48 months of age showed a trend toward efficacy in household contacts (3/131 placebo recipients V 0/162 rifampin recipients, P = .08).
Rotavirus in infant-toddler day care centers: Epidemiology relevant to disease control strategies