PCV and pneumococcal meningitis
The paediatric heptavalent pneumococcal conjugate vaccine (PCV7) was licensed in the United States in 2000. It is recommended for all children aged 2–23 months and for children aged 24–59 months who are at increased risk. Coverage in 2006 was estimated at >68% for four doses and >87% for three doses. Population trends in the incidence of pneumococcal meningitis have been assessed for 1998–2005.
Surveillance data from eight states were analysed, and a total of 1,379 cases of pneumococcal meningitis were identified. Between 1998 and 1999, and 2004 and 2005, the incidence fell by 30%, from 1.13 to 0.79 cases per 100,000 population. The decrease was 64% for children under 2 years of age and 54% for people aged 65 or older. For PCV7-serotype meningitis, there was an overall decline of 73%. PCV-related serotype disease decreased by 32%, but non-PCV-serotype disease increased by 61%. The proportions of cases due to non-PCV7 serotypes 19A, 22F and 35B increased significantly. Rates of antibiotic non-susceptibility were 28% (penicillin), 6% (chloramphenicol), 17% (meropenem) and 12% (cefotaxime). Between 1998 and 2003, the proportion of isolates non-susceptible to penicillin fell from 32% to 19%, but it rose again to 30% by 2005.
Rates of pneumococcal meningitis have fallen after the introduction of PCV7, but there has been an increase in meningitis due to non-PCV7 serotypes.
Hsu HE, et al. Effect of pneumococcal conjugate vaccine on pneumococcal meningitis. NEJM 2009;360:244–256.