Background: Introduction of the heptavalent conjugate vaccine for Streptococcus pneumoniae (PCV7) has led to a dramatic decline in meningitis by PCV7 serotypes, raising the possibility of similar trends by PCV7-related serogroups through cross-protection. A present concern, however, is of serotype replacement by pneumococci not related to PCV7 serogroups. If this occurs, there are currently few data to predict whether clinical outcomes will change substantially.
Methods: To address these questions, we analyzed medical records of 86 cases of pneumococcal meningitis treated at Nationwide Children's Hospital (1993-2004). Adverse neurologic sequelae and death were compared between cases with cerebrospinal fluid isolates characterized as vaccine-related serogroups-serotypes belonging to PCV7 or related to PCV7 serogroups, and those designated nonvaccine serogroups-serotypes neither belonging to PCV7 nor related to PCV7 serogroups. Serotype 19A, because of recent reports of increased incidence, was subanalyzed separately.
Results: Thirty-six of 86 (42%) subjects had serious complications, including 6 who died. All 6 deaths occurred in patients with vaccine-related serogroups. Deafness was the most common complication, occurring in 26 (32.5%) survivors. There was no difference in the frequency of total complications between PCV7-related and non-PCV7 groups: 5 of 12 (42%) for non-PCV7 serogroups versus 31 of 74 (42%) for PCV-related serogroups (OR: 1.0; 95% CI: 0.2-4.0). Serious outcomes occurred in 3 of 4 cases due to serogroup 19A. Non-PCV7 serogroups increased slightly at the end of the study period.
Conclusions: In children with pneumococcal meningitis, infections with non-PCV7 serogroups seem less likely to result in death. Among survivors, there is preliminary evidence of parity in neurologic sequelae between PCV7 and non-PCV7 serogroups.