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.
Kapsulirane bakterije so naprej razvrščene glede na serotipe, pri čemer je Haemophilus influenzae serotipa b najbolj patogen za ljudi in povzroča okužbe dihal in oči ter sepso in meningitis.