Serogroup C meningococcal conjugate vaccines: new preparations. Effective from age two months.

(1) Two unconjugated polyoside vaccines are available in France for the prevention of meningococcal infections: Vaccine meningococcique A+C from Pasteur Vaccines (against serogroups A and C) and Menomune from Aventis Pasteur MSD (against serogroups A, C, Y and W-135). Neither vaccine is effective in children under the age of two years. (2) 2002 saw the arrival of two conjugated vaccines directed solely against serogroup C meningococci and designed to protect infants from two months of age. Meningitec, marketed by Wyeth-Lederlé, is adsorbed to aluminium phosphate. The other conjugate vaccine is adsorbed to aluminium hydroxide and marketed under two names: Meninvact (Aventis Pasteur MSD) and Menjugate (Socopharm). (3) Immunogenicity studies have shown three advantages of conjugate vaccines over polyoside vaccines, namely a serologic response from as early as two months of age; a higher antibody titre 6 months after vaccination; and a larger increase in the antibody titre after booster injections. (4) Two-year follow-up data on a mass vaccination campaign launched in the United Kingdom in 1999 with Meningitec and Menjugate show that both vaccines have short-term efficacy in infants, children and adolescents. There was about an 80% fall in the number of invasive infections due to group C meningococci among vaccines, no such fall among unvaccinated subjects of the same age, and no major increase in the incidence of infections due to other serogroups. The number of deaths due to documented meningococcal infection showed a similar fall. (5) Most known adverse effects of these conjugate vaccines are mild and similar to those of other standard vaccines. They do not appear to be more frequent than with standard vaccines. Severe allergic reactions have occasionally been observed. A few deaths have followed vaccination with these products but appear to have been coincidental. There is no evidence that the two conjugate vaccines differ in terms of adverse effects. (6) Meningitec (suspension for injection) is more convenient to use than Meninvact and Menjugate (powders for injection). (7) Unlike the other companies concerned, Aventis Pasteur MSD failed to provide us with any documentation on their vaccine. (8) In practice, when specific vaccination against serogroup C meningococci is required (for case contacts or in areas of high incidence), Meningitec is currently the vaccine of choice. If Meningitec stocks are inadequate to deal with an outbreak, the second-line choice is Menjugate.