Pneumococcal serotype distribution and coverage of existing and pipeline pneumococcal vaccines

Abstract

Background: Next-generation pneumococcal conjugate vaccines (PCVs) target an expanding array of serotype antigens. We assessed the proportions of invasive pneumococcal disease (IPD) and pneumococcal acute respiratory infections (ARIs) caused by serotypes targeted by existing and pipeline PCVs, and annual U.S. pneumococcal disease burdens potentially preventable by these products.

Methods: We estimated serotype distribution and proportions of pneumococcal ARIs (acute otitis media [AOM; children only], sinusitis, non-bacteremic pneumonia) and IPD attributable to serotypes targeted by each PCV using Markov chain Monte Carlo approaches incorporating data from epidemiological studies and Active Bacterial Core Surveillance. We then estimated annual numbers of outpatient-managed ARIs, non-bacteremic pneumonia hospitalizations, and IPD cases potentially preventable by PCVs by multiplying disease incidence rates by PCV-targeted disease proportions and vaccine effectiveness estimates.

Results: In children, PCV15, PCV20, PCV24, PCV25, and PCV31 serotypes account for 16% (95% confidence interval: 15-17%), 31% (30-32%), 34% (32-35%), 43% (42-44%), and 68% (67-69%) of pneumococcal AOM, respectively. In adults, PCV15, PCV20, PCV21, PCV24, PCV25, and PCV31 serotypes account for 43% (38-47%), 52% (47-57%), 69% (64-73%), 65% (61-70%), 62% (57-67%), and 87% (83-90%) of pneumococcal non-bacteremic pneumonia. For IPD, 42-85% of pediatric and 42-94% of adult cases were due to PCV-targeted serotypes. PCV-preventable burdens encompassed 270,000-3,300,000 outpatient-managed ARIs, 2,000-17,000 pneumonia hospitalizations, and 3,000-14,000 IPD cases annually.

Conclusions: Across pneumococcal conditions, coverage and preventable burdens were lowest for PCV15 and highest for PCV31, with PCV21 also targeting sizeable burdens of adult disease. Comparative estimates of preventable disease burden may inform future policy.

Keywords: Streptococcus pneumoniae; acute otitis media; acute respiratory infection; invasive pneumococcal disease; pneumococcal conjugate vaccines; pneumococcus; pneumonia.