Pneumococcal disease prevention among adults: Strategies for the use of pneumococcal vaccines
Section snippets
Background
Streptococcus pneumoniae is a leading cause of disease and death among older adults in the United States. Pneumococcus causes invasive disease – bacteremia and meningitis – as well as pneumonia. Use of polysaccharide vaccine since the late 1970s should have resulted in the decline of invasive pneumococcal disease (IPD) among older adults but uptake has been slow, and the declines at a population level have not been documented [1], [2], [3]. Conversely, use of the conjugate vaccines (7-valent
Pneumococcal polysaccharide vaccine—PPSV23
The currently available pneumococcal polysaccharide vaccine, manufactured by Merck, Inc. (Pneumovax® 23), includes 23 purified capsular polysaccharide antigens of S. pneumoniae (serotypes 1, 2, 3, 4, 5, 6B, 7F, 8, 9N, 9V, 10A, 11A, 12F, 14, 15B, 17F, 18C, 19A, 19F, 20, 22F, 23F, and 33F). This vaccine was licensed in the United States in 1983 and replaced an earlier 14-valent formulation that was licensed in 1977.
The first PPSV licensed in the US was PPSV14. Capsular polysaccharides included in
Recent changes in recommendations
In 2011, PCV13 was approved by the FDA for use among adults ≥50 years old to prevent pneumonia and invasive disease caused by the serotypes in the vaccine. It was approved under the FDA's accelerated approval pathway based on non-inferior immunogenicity compared to PPSV23. As a condition of licensure, the vaccine manufacturer agreed to conduct a randomized controlled trial of PCV13 against pneumococcal pneumonia in adults ≥65 years old [9]. The ACIP elected to recommend PCV13 for
Immune response to PCV13
FDA approval of PCV13 in 2011 for adults was based on immunogenicity studies that compared antibody responses to PCV13 with antibody responses to PPSV23. In two randomized, multicenter, immunogenicity studies conducted in the United States and Europe, adults aged 50 years and older received a single dose of PCV13 or PPSV23. Functional antibody responses were measured 1 month after vaccination using an opsonophagocytic activity (OPA) assay. In adults aged 60 through 64 years naïve to
Efficacy of PPSV23 against IPD and pneumonia
While the results of studies evaluating PPSV23 efficacy and effectiveness against IPD are consistent with protection against IPD among generally healthy young adults and among the general population of older persons, studies of non-bacteremic pneumococcal pneumonia among adults have yielded contradictory conclusions. The meta-analysis by Moberley et al. [20] reported PPSV efficacy of 73% against vaccine type presumptive pneumococcal pneumonia. However, of the four studies contributing to this
Rationale and evidence for PCV13 and PPSV23 use in series
In 2013, of 13,500 cases of IPD estimated to have occurred among adults aged ≥65 years, approximately 20–25% of cases were caused by PCV13 serotypes and were potentially preventable with the use of PCV13 in this population (CDC unpublished data, 2013) [30]. An additional 38% of IPD among adults aged ≥65 years was caused by serotypes unique to PPSV23. Given this high proportion of IPD caused by serotypes unique to PPSV23, broader protection, especially against IPD, should be expected to be
Changing epidemiology and implications for use of pneumococcal vaccines among adults
Substantial reductions in the incidence of pneumococcal disease caused by serotypes in the 7-valent pneumococcal conjugate vaccine were noted among adults shortly after routine vaccination of children with PCV7 began in 2000 [36], and these reductions continued to occur through 2009 [4]. Recent studies demonstrate reductions in IPD caused by most serotypes in PCV13 across all age groups following only 3 years of PCV13 use among children (Fig. 1) [30]. Among adults of different age groups,
Summary
The ACIP has recently made recommendations for the use of pneumococcal vaccines in healthy adults >65 years. These recommendations for both PCV13 and PPSV23 were based on the remaining burden of illness among adults caused by PCV13 serotypes and by those serotypes included in PPSV23 and not PCV13. The committee also considered the importance of non-bacteremic pneumococcal pneumonia in determining the overall burden of pneumococcal disease among adults and the evidence from CAPiTA confirming the
Conflict of Interest
None declared.
This article is being published concurrently in the American Journal of Preventive Medicine and Vaccine. The articles are identical except for stylistic changes in keeping with each journal's style. Either of these versions may be used in citing this article. Publication of this article was supported by Merck and Novartis.
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