Invasive pneumococcal disease after routine pneumococcal conjugate vaccination in children, England and Wales

Abstract

We assessed known risk factors, clinical presentation, and outcome of invasive pneumococcal disease (IPD) in children 3-59 months of age after introduction of the 7-valent pneumococcal conjugate vaccine (PCV7) in England and Wales. During September 2006-March 2010, a total of 1,342 IPD episodes occurred in 1,332 children; 14.9% (198/1,332) had comorbidities. Compared with IPD caused by PCV7 serotypes (44/248; 17.7%), comorbidities were less common for the extra 3 serotypes in the 10-valent vaccine (15/299; 5.0%) but similar to the 3 additional PCV13 serotypes (45/336; 13.4%) and increased for the 11 extra serotypes in 23-valent polysaccharide vaccine (PPV23) (39/186; 21.0%) and non-PPV23 serotypes (38/138; 27.5%). Fifty-two (3.9%) cases resulted from PCV7 failure; 9 (0.7%) case-patients had recurrent IPD. Case-fatality rate was 4.4% (58/1,332) but higher for meningitis (11.0%) and children with comorbidities (9.1%). Thus, comorbidities were more prevalent in children with IPD caused by non-PCV13 serotypes and were associated with increased case fatality.

Figure

IPD clinical cases in PCV7-eligible children since PCV7 introduction, England and Wales, September 4, 2006–March 31, 2010. A) Distribution of cases. Black bar sections, bacteremia; dark gray bar sections, lower respiratory tract infection; light gray bar sections, meningitis; white bar sections, other. B) Proportion of serotyped cases caused by PCV7 serotypes in healthy children (dashed line) and children with comorbidities (solid line). The prevalences of comorbidity among IPD cases during the 4 time periods were 13,5%, 17.7%, 17.0%, and 10.7%, and the case-fatality rates were 5.6%, 4.3%, 4.3%, and 3.0%, respectively. *Data included for 7 months only. IPD, invasive pneumococcal disease; PCV7, 7-valent pneumococcal conjugate vaccine.