Invazive Haemophilus influenzae Infections in Two Children who Vaccinated with Haemophilus influenzae type b Vaccine

Haemophilus influenzae type b (Hib) causes invasive infectious diseases such as meningitis, bacteremia and pneumonia. Invasive Hib infections occur mostly in children under five years old, but in the first 6-12 months of their life they are at greatest risk for the disease. After the introduction of conjugate Hib vaccines, the incidence of invasive Hib infections has decreased. There are still some cases of invasive Hib disease immunization with conjugate Hib vaccine. There is no evidence that non-type b infections have increased in frequency, but some cases have been reported. Patients with immune deficiency syndromes can also have invasive Hib infections because of inadequate antibody responses. Here, we present two cases with invasive Hib infections immunization with conjugate Hib vaccines.