Immunity to Haemophilus influenzae type b on sample population from central Italy

• Published in: Vaccine Vol. 10; no. 9; pp. 627 - 630
• Main Authors: Sansoni, A., Rappuoli, R., Viti, S., Costantino, P., Fanti, O., Cellesi, C.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 1992; Elsevier
• Subjects: Adolescent; Antibodies, Bacterial - blood; Bacterial Capsules; Bacterial Vaccines - therapeutic use; Bacteriology; Biological and medical sciences; capsular polysaccharide; Child; Child, Preschool; Epidemiology; Female; Fundamental and applied biological sciences. Psychology; Haemophilus Infections - epidemiology; Haemophilus Infections - immunology; Haemophilus Infections - prevention & control; Haemophilus influenzae - classification; Haemophilus influenzae - immunology; Haemophilus influenzae type b immunity; Haemophilus Vaccines; Humans; Immunity, Innate; Infant; Infant, Newborn; Italy - epidemiology; Male; Microbiology; Polysaccharides, Bacterial - therapeutic use; Sampling Studies; Seroepidemiologic Studies; Italy; Europe; Italy, Siena; capsular polysaccharide; Haemophilus influenzae type b immunity; Pasteurellaceae; Microorganism capsule; Human; Bacteria; Natural immunity; Serology; Epidemiology; Polysaccharide; Age; Haemophilus influenzae
• ISSN: 0264-410X; 1873-2518
• DOI: 10.1016/0264-410X(92)90445-P

A study on natural immunity to Haemophilus influenzae type b (Hib) was carried out in the province of Siena on 474 subjects ranging in age from 3 days to 70 years. The titration of antibody to capsular polysaccharide (PRP) was performed by the radioantigen-binding assay (RABA) method. A total of 66.67% of the population studied presented an antibody level considered to be protective (⩾0.15 μg ml −1). Seropositivity was 5.7% in the 5–7 month age group and 29.09% in the 8–17 month age group. This rose progressively in successive age groups reaching 79.54% between 4 and 6 years old and a value >90% after 7 years old. From 3 to 17 months even the geometric mean of antibodies to PRP was below the protective limit. Our data indicate that, even in Italy, the majority of the infant population is not protected against H. influenzae, and therefore that vaccination should also be introduced in this country.