BACKGROUND: Implementation of the Haemophilus influenzae type b (Hib) conjugate vaccine brought about a reduction in the number of cases and morbidity from type B but increase in nontypeable strain infections.

CASE REPORT: We had 3 cases of invasive non type Hemophilus influenzae (NTBHI) in immunocompromised children. The first was a fully vaccinated 2-year-old male with a history of pseudomonas sepsis who presented with 1 day of lethargy, fever, vomiting, and diarrhea. Blood culture was positive for Haemophilus influenzae e and cerebrospinal fluid (CSF) confirmed meningitis. Immune deficiency and genetic testing revealed X-linked agammaglobulinemia. The second case was a 4-year-old male, status post liver transplantation, who presented with pneumonia, with positive blood culture for H. influenzae. The last case was of a 2-year-old male with H. influenzae biotype VI in both blood and CSF cultures, who on follow-up was confirmed to have hypogammaglobulinemia.

CONCLUSIONS: For children diagnosed with an invasive disease caused by NTBHI, a workup for immunodeficiency could be warranted. With the appearance of nontype b serotypes, more studies are needed to determine epidemiology and virulence of these types, and their clinical relevance – perhaps developing a new vaccine to cover nontype b stereotypes, especially for immunodeficient patients.

Keywords: Haemophilus Infections, Haemophilus influenzae, Haemophilus influenzae type b, Immunocompromised Host, Pediatrics, Child, Preschool