Invasive <EMPH TYPE="ITAL">Haemophilus influenzae</EMPH> Disease in Alaskan Residents Aged 10 Years and Older Before and After Infant Vaccination Programs

Abstract

The overall statewide incidence of invasive H influenzae infections in unimmunized persons aged 10 years and older decreased after the initiation of an infant Hib vaccine program, perhaps by decreasing Hib carriage in child reservoirs. An increase in non-serotype b strains was observed. This trend justifies the need for continued surveillance of invasive disease caused by H influenzae. JAMA. 2000.

Epidemiology ofHaemophilus influenzaeSerotype a, North American Arctic, 2000–2005

“…Clinical manifestations of invasive Hia disease were similar to those of invasive Hib disease in the prevaccine era (29). Meningitis was more common among Hia infections than in infections caused by encapsulated non-a and non-typeable Hi infections (37% vs. 24% and 12%, respectively, p = 0.05); conversely, pneumonia was less common (32% Hia vs. 41% encapsulated non-a H. infl uenzae and 40% nontypeable H. infl uenzae); however, this fi nding was…”

“…However, the potential for serotype replacement remains a concern (16). Three population-based studies have documented small increases in the incidence of non-type b H. infl uenzae disease after the introduction of the Hib conjugate vaccine (28)(29)(30). Several recent studies conducted in different countries have demonstrated a predominance of serotype a disease.…”

pgi Genotyping Is a Surrogate for Serotyping of Encapsulated Haemophilus influenzae

“…The incidence of serious infection caused by non-type b encapsulated H. influenzae is currently much lower than that of Hib infections in the prevaccine era; however, for several reasons, public health experts recommend continued surveillance of invasive disease caused by these bacteria (21). First, invasive infections due to non-type b encapsulated H. influenzae have increased in relative importance with the decline of Hib disease (7,18,21).…”

The continuing role ofHaemophilus influenzaetype b carriage surveillance as a mechanism for early detection of invasive disease activity

“…2,12 A study of Native Alaskans reported Hib oropharyngeal carriage as high as 9.3% in fully vaccinated under five year old children. 54 Other studies in Alaska found carriage rates up to 13.2% in a 97% vaccinated population, with authors concluding that carriage is the driving force behind Hib disease resurgence in remote Alaska. 53 More recently health researchers have reported resurgence of Hib carriage UK, in fully vaccinated school children.…”