The clinical impact of pneumococcal conjugate vaccines

Progress has been made in the development of a vaccine against pneumococcal diseases of infancy and childhood. In one of the largest demonstrations of this progress, a randomized controlled clinical trial of a heptavalent pne umococcal conjugate vaccine in 38,000 children recently showed the vaccine to be safe and; immunogenic. These infants were in a managed care organizat ion and were randomized at 2 months to either a 7-valent pneumococcal conju gate vaccine or the meningococcal conjugate vaccine. The preliminary result s also showed that the first 17 cases of invasive disease with vaccine sero types of the pneumococcus all occurred within the control group. Full effic acy results in confirmed episodes of acute otitis media, pneumococcal pneum onia with positive,X rays, bacteremia, and meningitis will be reported soon . Based on immunogenicity, safety, and preliminary efficacy data, the 7-val ent conjugate vaccine is likely to be much more effective than existing pol ysaccharide vaccines in children. After licensure of the various vaccines n ow in development, continued surveillance of pneumococcal serotypes will be necessary to maintain maximum effectiveness.