A review of Haemophilus influenzae disease in Europe from 2000-2014: challenges, successes and the contribution of hexavalent combination vaccines.

INTRODUCTION: The development of diphtheria-tetanus-acellular pertussis-Haemophilus influenzae type b (Hib) conjugate vaccine combinations culminated with hexavalent vaccines, the largest, most complex vaccine combinations in the immunization calendar. Hexavalent vaccines are used widely in Europe and are co-administered with multiple other recommended vaccines. Hib immunogenicity may reduce when combined with acellular pertussis antigens, or in some co-administrations. We reviewed the epidemiology of H. influenzae disease in Europe aiming to evaluate the current level of Hib control and indirectly assess the effectiveness against Hib of GSK's hexavalent vaccine in 10 countries where it is/has been used almost exclusively. Areas covered: We reviewed surveillance data from the European Union Invasive Bacterial Infections Surveillance Network and the European Surveillance System database from 1999-2014 and extracted case and incidence/notification rates (per 100,000 population) of invasive H. influenzae disease. We included age and serotype/strains distribution among countries in the European Union/European Economic Area region that reported to the European Centre for Disease Prevention and Control surveillance system. Expert commentary: The impact of Hib vaccination in Europe is sustained, testifying to continued effectiveness against invasive Hib disease after the implementation of hexavalent vaccines into immunization programs, which, since 2006, has been almost exclusively GSK´s hexavalent DTPa-HBV-IPV/Hib vaccine.