Haemophilus influenzae type b infections in adults.

31 cases of invasive Haemophilus influenzae type b infections occurred in adults in Denmark during a period of 2 years and 5 months corresponding to an incidence of 0.3/100,000/year. Only 6 patients had no underlying condition. The incidence of H. influenzae type b infections in adults will probably rise in the future, because the increasing use of therapeutic measures affecting the immune system will lead to an increase in the number of susceptible patients.