Seroprevalence of bactericidal antibody against Neisseria meningitidis serogroup C in pre-vaccinal era: The Italian epidemiological scenario

Meningococcal disease is particularly severe. The case-fatality rate is 7.78% in Europe and 10–14% in the USA.This paper reports the results of a sero-epidemiological study in Italy on meningitis due to Meningococcus C before the introduction of the monovalent conjugate vaccine.In 2003–2004, a total of 577 sera were collected in 17 of the 20 Italian Regions. Serum Bactericidal Assay (SBA) was performed by using rabbit complement serum according to standardized SBA. The results showed that the percentages of protected subjects decreased from 6 to 12 months of age, increased from 1 to 4 years, decreased again until the age of 8 years and from 13 to 16 years, and were particularly high in 9- and 17-year-old subjects.The geometric mean titre of bactericidal antibodies (SBAbs GMT) was low in subjects under 1 year of age, significantly increased in 1–9-year-old children and decreased in adolescents and young adults.Finally, in each one-year age-group, low levels of antibodies were observed in subjects under 1 year of age, in 10-year-old subjects and in 14–16-year-old adolescents. High titres were observed in 3-, 8-, 9- and 17-year-old subjects. Our results therefore indicate that meningococcus C has the highest probability of spreading among 1–4, 8–10 and 14–17-year-old subjects in Italy.