A TRIAL OF A GROUP-A PLUS GROUP-C MENINGOCOCCAL POLYSACCHARIDE-PROTEIN CONJUGATE VACCINE IN AFRICAN INFANTS

The safety and immunogenicity of a group A plus group C meningococcal polysaccharide-CRM(197) conjugate vaccine was evaluated in 304 8- to 1 0-week-old Gambian infants. Infants were immunized with one, two, or t hree doses of conjugate vaccine or with two doses of a meningococcal A plus C polysaccharide vaccine. The conjugate vaccine produced few sys temic side effects, and local reactions were similar to those produced by the polysaccharide vaccine. Postvaccination group A meningococcal polysaccharide antibody levels, measured by ELISA, increased progressi vely after one, two, or three doses of conjugate vaccine. However, one dose of conjugate vaccine given at the age of 6 months induced a high er group C meningococcal antibody response than did two doses of conju gate vaccine given at 2 and 6 months. Two doses of conjugate vaccine i nduced higher levels of antibody than did two doses of polysaccharide vaccine. Thus, this new meningococcal conjugate vaccine proved to be s afe and immunogenic.