Haemophilus influenzae Serotype b Vaccine Failure: What Is the Significance of Antibody Levels?

zae serotype b (Hib) conjugate vaccine has been a major step in the prevention of meningitis, epiglottitis, and other mani-festations of invasive Hib disease. Because these diseases occur mainly in children, vaccination during infancy prevents the vast majority of cases within a few years. The optimal schedule for Hib vaccination is still a matter of debate. In the United Kingdom, one of the first countries to im-plement Hib conjugate vaccination in the infant immunization program (in 1992), a vaccine scheme of 3 doses at 2, 3, and 4 months of age was initially applied. To-gether with a catch-up campaign, thi