Vaccines for Nontypeable Haemophilus influenzae: the Future Is Now

Abstract

ABSTRACTInfections due to nontypeableHaemophilus influenzaeresult in enormous global morbidity in two clinical settings: otitis media in children and respiratory tract infections in adults with chronic obstructive pulmonary disease (COPD). Recurrent otitis media affects up to 20% of children and results in hearing loss, delays in speech and language development and, in developing countries, chronic suppurative otitis media. Infections in people with COPD result in clinic and emergency room visits, hospital admissions, and respiratory failure. An effective vaccine would prevent morbidity, help control health care costs, and reduce antibiotic use, a major contributor to the global crisis in bacterial antibiotic resistance. The widespread use of the pneumococcal conjugate vaccines is causing a relative increase inH. influenzaeotitis media. The partial protection againstH. influenzaeotitis media induced by the pneumococcalH. influenzaeprotein D conjugate vaccine represents a proof of principle of the feasibility of a vaccine for nontypeableH. influenzae. An ideal vaccine antigen should be conserved among strains, have abundant epitopes on the bacterial surface, be immunogenic, and induce protective immune responses. Several surface proteins ofH. influenzaehave been identified as potential vaccine candidates and are in various stages of development. With continued research, progress toward a broadly effective vaccine to prevent infections caused by nontypeableH. influenzaeis expected over the next several years.