Invasive pneumococcal disease after implementation of 13-valent conjugate vaccine

Pui-Ying Iroh Tam, Lawrence C. Madoff, Brandon Coombes, Stephen I. Pelton

Research output: Contribution to journalArticlepeer-review

47 Scopus citations


OBJECTIVE: To examine whether there is a different clinical profile and severity of invasive pneumococcal disease (IPD) in children caused by nonvaccine types in the era of 13-valent pneumococcal conjugate vaccine (PCV13). METHODS: Observational study of childhood IPD in Massachusetts based on state public health surveillance data comparing pre-PCV13 (2007-2009) and post-PCV13 (2010-2012) eras. RESULTS: There were 168 pre-PCV13 cases of IPD and 85 post-PCV13 cases of IPD in Massachusetts children ≥5 years of age. PCV13 serotypes declined by 18% in the first 2 years after PCV13 use (P = .011). In the post-PCV13 phase, a higher proportion of children were hospitalized (57.6% vs 50.6%), and a higher proportion of children had comorbidity (23.5% vs 19.6%). Neither difference was statistically significant, nor were comparisons of IPD caused by vaccine and nonvaccine types. Children with comorbidities had higher rates of IPD caused by a nonvaccine type (27.6% vs 17.2%; P = .085), were more likely to be hospitalized (80.4% vs 50%; P < .0001), and were more likely to have a longer hospital stay (median of 3 days vs 0.5 days; P = .0001). CONCLUSIONS: Initial data suggest that nonvaccine serotypes are more common in children with underlying conditions, who have greater morbidity from disease. In the post-PCV13 era, a larger proportion of patients are hospitalized, but mortality rates are unchanged. Routine vaccination with PCV13 may not be enough to reduce the risk in patients with comorbidity.

Original languageEnglish (US)
Pages (from-to)210-217
Number of pages8
Issue number2
StatePublished - Aug 1 2014


  • Children
  • Comorbidity
  • Conjugate vaccine
  • Invasive pneumococcal disease
  • Severity


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