7-valent pneumococcal conjugate vaccine: new preparation. Prevents rare invasive infections in infants.Prescrire Int. 2002 Feb; 11(57):7-10.PI
(1) Infants under two years of age are the children most exposed to invasive pneumococcal infections (meningitis and bacteraemia). The estimated incidence in France is about 45 cases per year per 100,000 in the first year of life. The 23-valent pneumococcal polysaccharide vaccine is ineffective in children under two years of age. (2) Marketing authorization has now been granted for a 7-valent pneumococcal conjugate vaccine for children under two years. It is the first pneumococcal vaccine specifically designed for this age group. (3) Its immunogenicity in 2 year old children has been carefully documented. (4) A comparative, randomised, double-blind trial involving nearly 38,000 Californian infants showed a lower incidence of both all invasive pneumococcal infections (approximately 1 case avoided per 400 children vaccinated), and those due to the 7 serotypes covered by the vaccine. (5) These results are not directly applicable to France, where the pneumococcal serotype distribution (especially the 7 serotypes covered by the vaccine) seems to be somewhat different, and where the incidence of invasive pneumococcal infections is much lower. (6) The 7-valent vaccine has not been assessed adequately in children who are at high risk for invasive pneumococcal infection. Some small studies of children with sickle-cell disease show adequate immunogenicity. (7) The known adverse effects of the 7-valent vaccine are acceptable, mainly comprising local reactions and fever. (8) The risk of an epidemiological shift towards serotypes not covered by the vaccine (through pharyngeal carriage and invasive infection) cannot been ruled out. In otitis media, an increase in pneumococcal infections due to serotypes not covered by the vaccine negates the benefit of vaccination. (9) In practice, considering the severity of invasive pneumococcal infections and the documented efficacy and safety of the 7-valent conjugate vaccine, vaccination is warranted for individual children under two years of age, especially those at risk, but epidemiological monitoring and pharmacovigilance must continue.