, a gram negative coccobacillus, is divided into unencapsulated (non-typable) and encapsulated strains. The latter are further classified into serotypes, with the Haemophilus influenzae serotype b being the most pathogenic for humans, responsible for respiratory infections, ocular infection, sepsis and meningitis.
Haemophilus influenzae serotype b (Hib) is the most common cause of bacterial meningitis in children aged two months to five years, in those countries where suitable vaccination programmes are not in place.
Children start showing symptoms of meningitis after a probable incubation period of about 2– 4 days and clinical manifestations tend to evolve rapidly. Even with adequate and prompt antibiotic treatment, mortality can reach up to 10% of cases. Vaccine prophilaxis is therefore of paramount importance, in order to protect children.