Prevalence of Bactericidal Antibodies to Haemophilus influenzae, Type b

Sera from 1,205 persons, with a broad age span, were tested for bactericidal activity against Haemophilus influenzae, type b. The lowest prevalences of such antibodies were found among children aged one through four years and among adults over the age of 80 years. No positive correlation was observed between prevalence of antibodies and race, gravidity, or socioeconomic status. The highest prevalence was found among the parents of children who had had H. influenzae epiglottitis previously.