Pneumococcal conjugate vaccine use in adults

ABSTRACT

Streptococcus pneumoniae is a leading cause of illness and death in adults. A polysaccharide vaccine has been available for over 30 years, but despite significant use, the public health impact of this vaccine has been limited. The 13-valent pneumococcal conjugate vaccine (PCV13) has been licensed by the US Food and Drug Administration and other international regulatory authorities with the assumption that induction of a T cell–dependent immune response and noninferior immunogenicity to vaccine antigens when compared with the polysaccharide vaccine would be important to satisfy a significant unmet medical need. PCV13 efficacy against vaccine-type pneumococcal community-acquired pneumonia was confirmed in a large randomized controlled trial in older adults and its use is now increasingly recommended globally.

KEYWORDS:

• Community-acquired pneumonia
• invasive pneumococcal disease
• pneumococcal conjugate vaccine
• Streptococcus pneumoniae
• adults

Financial & competing interests disclosure

All authors are current or former employees of Pfizer and may hold stock or stock options. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. Medical writing support was provided by Daniel E. McCallus, PhD, at Complete Healthcare Communications, LLC, and was funded by Pfizer Inc.

Key issues

• S. pneumoniae is a leading cause of serious illness, with invasive manifestations including nonbacteremic and bacteremic pneumonia, meningitis and sepsis.

• The use of PCVs in childhood pneumococcal immunization programs successfully reduced the incidence of pneumococcal disease in all age groups; however, there remains a significant burden of pneumococcal pneumonia in adults, including disease caused by serotypes in the vaccine.

• Nonbacteremic pneumococcal pneumonia is the most common pneumococcal disease manifestation in adults and the only licensed pneumococcal vaccine that has been shown to prevent nonbacteremic pneumococcal pneumonia is PCV13.

• Two pneumococcal vaccines are currently available for adults at risk for pneumococcal disease, PPSV23 and PCV13.

• PCV13 elicits generally higher antipneumococcal immune responses compared with PPSV23 for the serotypes in common and for serotype 6A, not in the polysaccharide vaccine.

• In adults, administering a dose of PPSV23 before a dose of PCV13 may negatively affect the immune response to PCV13, whereas a dose of PCV13 before a dose of PPSV23 may enhance the response to the common serotypes.

• A randomized controlled trial from 2008 to 2013 among approximately 85,000 adults aged ≥65 years demonstrated 45.6% (95% CI: 21.8%–62.5%) efficacy of PCV13 against all VT pneumococcal pneumonia, 45.0% (95% CI: 14.2%–65.3%) efficacy against VT nonbacteremic pneumococcal pneumonia and 75.0% (95% CI: 41.4%–90.8%) efficacy against VT IPD.

• The safety database in adults with PCV13 is substantial and demonstrates a positive risk-benefit profile.

• Next-generation conjugate vaccines with expanded serotype representation are likely to replace PCV13 before a protein serotype-independent vaccine can be successfully developed and implemented. Thus, for the foreseeable future, appropriate protection of adults at risk for pneumococcal CAP will rely on vaccination with PCV13.

• Currently, immunocompetent adults aged 19–64 years living with chronic medical conditions such as heart disease, lung disease and diabetes mellitus are the only individuals at increased risk for pneumococcal disease for whom PCV13 is not routinely recommended in the United States.

• Given the available evidence, PCV13 vaccination may provide benefit to individuals aged 19–64 years living with at-risk conditions.