The Analysis of Invasive Haemophilus influenza Infections During the Past Thirteen Years

Abstract

Since the introduction of the Haemophilus influenzae type b (Hib) conjugated vaccine for infants, the incidence of invasive Hib disease in children has decreased dramatically, while non-typeable and capsulated strains other than serotype b which were not contained in the Hib vaccine were thought to be increasing. We have studied invasive H. influenzae disease of all age group who visited our hospital. A total of 20 patients were included as analysis objects between January 2003 and October 2015. Of the 20 patients, 11 (median age 2 years old, range 13 days-5 years old) were children and 9 (median age 71 years old, range 29-88 years old) were adults. All pediatric cases were documented before 2010, in which the analyzed capsular typing of those were all type b. However 8 of 9 cases of adult patients occurred after 2012 and the capsular typing of these cases was non-typeable H. influenzae (NTHi) (6 cases), type e (1 case) and unknown (2 cases). Infected organs were meningitis (5 cases), pneumoniae (5 cases), epiglottitis (5 cases), cholangitis (3 cases) and intra-uterine infection (1 case). Invasive NTHi infection may have increased after the routine vaccination with the Hib vaccine for infants.