Epidemiology of invasive Haemophilus influenzae type b disease and the susceptibility of aggregate hosts.
Haemophilus influenzae type b bacteria has been responsible for recent increase in invasive disease in the adult population of the United States. This increase in H. influenzae infections is greatest in individuals above 65 years of age. A plausible explanation for this increase may be the changes observed in the epidemiology of invasive H. influenzae type b (Hib) disease and the susceptibility of aggregate hosts. A comprehensive literature review was conducted from multiple data sources, such as PubMed, MEDLINE, CDC, journal articles, reference texts, and Internet websites. The increase in infectious disease caused by H. influenzae type b bacteria is affecting individuals 65 years and older and is preventable. However, Hib vaccines are currently approved for the pediatric population and susceptible adults with certain immune deficiencies. New trends in this invasive disease require reevaluation of current guidelines to include individuals 65 years and older as target population for the polysaccharide Hib vaccine. The changing epidemiology of H. influenzae type b bacteria requires reevaluation of current immunization guidelines regarding Hib vaccination so that it is included in the immunization schedule for adults aged 65 and above.