ABSTRACT: For nearly 50 years, vaccination of high-risk individuals has led to a decrease in the incidence of invasive pneumococcal diseases, such as bacteremia and meningitis. However, for older adult populations, PPSV23 (Pneumovax 23) has not demonstrated consistent protection against pneumococcal pneumonia in clinical trials. Based on recent data from the CAPiTA trial showing both decreased episodes of community acquired pneumonia and a reduction of invasive pneumococcal disease, the CDC’s Advisory Committee on Immunization Practices recently updated the vaccination schedule to include both PPSV23 and PCV13 (Prevnar 13) for those aged >65 years.
Infections from Streptococcus pneumoniae, also referred to as pneumococcus, remain a significant public health burden. Presenting as major syndromes such as pneumonia, bacteremia, or meningitis, pneumococcal infections cause significant morbidity and mortality. In 2011, more than 35,000 cases of invasive pneumococcal disease (defined as infection of a normally sterile site) caused 4,200 deaths in the United States.1 Of these cases, the adult population aged >65 years, together with pediatric patients aged <5 years, experienced the highest incidence of disease.1 S pneumoniae remains the most commonly identified pathogen in community acquired pneumonia (CAP), which is the most common presentation of pneumococcal disease.2
Most strains of this gram-positive, alpha-hemolytic facultative anaerobe are encapsulated, leading to its pathogenic virulence in humans. These antigenic capsular polysaccharides serve as the classification system for S pneumoniae, with over 90 identified serotypes.1 Although all serotypes may cause serious disease, a relatively limited number cause invasive disease, making vaccination programs fundamentally effective.1,3
History and Effectiveness
Attempts to develop a vaccine against S pneumoniae began as early as 1911, with renewed interest developing in the 1960s; patients were still dying from pneumococcal disease despite treatment with antibiotic therapy.1 Two types of vaccines are currently available: a polysaccharide vaccine composed of purified preparations of pneumococcal capsular polysaccharides and a conjugate vaccine of capsular polysaccharides linked to a nontoxic variant of a diphtheria toxin.1,3 The first pneumococcal vaccine was FDA-approved in 1977 and contained purified antigen from 14 types of pneumococcal bacteria. This was replaced in 1983 with a 23-valent polysaccharide vaccine (PPSV23, Pneumovax 23; Merck) containing antigens from 23 types of S pneumoniae that are known to cause 88% of bacteremic pneumococcal disease.1 In 2000, the first conjugate vaccine was developed (PCV7) but has since been replaced by the currently available PCV13 (Prevnar 13; Pfizer) in 2010.1
PPSV23 vaccination has demonstrated an overall prevention rate of 60% to 70% of invasive disease. It is important to note that PPSV23 has not demonstrated consistent protection against noninvasive pneumococcal pneumonia in clinical trials, and for this reason providers should avoid referring to PPSV23 as a “pneumonia vaccine.” 1,3 PCV13 has been shown to prevent 75% of invasive pneumococcal disease in adults >65 years of age and is 45% effective in preventing non-invasive pneumonia caused by the 13 strains it covers.1
ACIP Recommendation
In August 2014, the CDC’s Advisory Committee on Immunization Practices (ACIP) added PCV13 to the adult immunization schedule for those aged >65 years. Previously, ACIP recommended only PPSV23 for older adults.3 Now, both PCV13 and PPSV23 should be administered routinely to all adults >65 years of age (Figure 1). This updated recommendation was based on two factors: the impact of PCV13 use in children on disease in adults (via decreased transmission) and recent data regarding efficacy of PCV13 against non-invasive pneumococcal disease, such as pneumonia, in adults.3 This recommendation for routine PCV13 vaccination among adults >65 years of age will be re-evaluated in 2018 and revised if needed.3
The evidence supporting the use of PCV13 in older adults comes from the Community Acquired Pneumonia Immunization Trial (CAPiTA).4 This randomized, double-blind, placebo-controlled trial analyzed 84,496 patients aged >65 years in the Netherlands. It was designed to assess the efficacy of PCV13 in the prevention of a first episode of vaccine-type CAP, nonbacteremic and noninvasive pneumococcal CAP, and invasive pneumococcal disease. Patients were randomized to receive either a one-time dose of PCV13 or placebo. Patients who received PCV13 developed 45.6% fewer first episodes of vaccine-type preventable CAP (49 patients vs. 90 patients; P <.001).4 Forty-five percent fewer episodes of nonbacteremic and noninvasive vaccine-type CAP occurred in the PCV13 group (33 patients vs. 60 patients; P = .007).4 Additionally, these patients had 75% fewer first episodes of invasive pneumococcal disease (7 patients vs. 28 patients; P <.001).4
Vaccine Administration
PCV13 and PPSV23 are inactivated vaccines that are administered IM. Both are well tolerated, with the most common side effects being redness, pain, and swelling at the injection site. Serious or life-threatening reactions from the vaccines are very rare. Individuals with a severe allergy to any component of either vaccine should not receive the vaccine. Additionally, vaccination with PCV13 is contraindicated in individuals who are known to have a severe allergic reaction to any diphtheria toxoid–containing vaccine. Any adverse event occurring after the administration of either vaccine should be reported to the Vaccine Adverse Event Reporting System (VAERS).3,5
Concomitant administration of PCV13 and PPSV23 is contraindicated. However, administration of PCV13 and the trivalent inactivated influenza vaccine (TIV) has been proven safe and immunogenic.3,5 Data are currently unavailable regarding coadministration of PCV13 and other vaccines in adults.3,5
It is recommended that in pneumococcal vaccine–naïve patients, PCV13 be administered first, followed by PPSV23 from 6 to 12 months later. The minimum interval between sequential administration of the vaccines is 8 weeks.3,5 Adults >65 years of age who previously received one or more doses of PPSV23 should also receive a dose of PCV13 if not previously vaccinated.3,5 The dose of PCV13 should be given at least 1 year after the most recent dose of PPSV23.3,5 If an individual is a candidate for an additional dose of PPSV23 (due to a previous administration between the ages of 19 and 64 years for an indication such as an immunocompromising condition or anatomical or functional asplenia), the subsequent dose should be given 6 to 12 months after PCV13 administration and at least 5 years after the most recent PPSV23 dose.3,5
Medicare Reimbursement
Historically, Medicare Part B provided reimbursement for only one pneumococcal vaccine once in a beneficiary’s lifetime.6 The Centers for Medicare and Medicaid Services (CMS) has updated its policy to reflect the new ACIP recommendation. For patients requiring a different, second vaccination, CMS will cover the second vaccination 1 year after the first was administered.6 Note that the interval between the two types of vaccinations must be 11 or more months, which is a longer period than the minimum of 8 weeks recommended by ACIP.6
Conclusion
With these new, evidence-based recommendations from the ACIP, pharmacists can play a major role in prevention of pneumococcal disease by increasing vaccination rates. Opportunities include educating both healthcare professionals and patients, ensuring that vaccination histories are up-to-date, administering vaccines, and counseling patients.
REFERENCES
1. Centers for Disease Control and Prevention. Hamborsky J, Kroger A, Wolfe S, eds. Epidemiology and Prevention of Vaccine-Preventable Diseases. 13th ed. Washington DC: Public Health Foundation; 2015. Updated May 15, 2015. www.cdc.gov/vaccines/pubs/pinkbook/index.html. Accessed June 15, 2015.
2. Musher DM, Thorner AR. Community-acquired pneumonia. N Engl J Med. 2014;371:1619-1628.
3. Tomczyk S, Bennett NM, Stoecker C, et al. Centers for Disease Control and Prevention. Use of 13-valent pneumococcal conjugate vaccine and 23-valent pneumococcal polysaccharide vaccine among adults aged ≥65 years: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR. Morb Mortal Wkly Rep. 2014;63:822-825.
4. Bonten M, Huijt S, Bolkenbaas M, et al. Polysaccharide conjugate vaccine against pneumococcal pneumonia in adults. N Engl J Med. 2015; 372:1114-1125.
5. Centers for Disease Control and Prevention. Pneumococcal vaccines (PCV13 and PPSV23). Addressing common questions about pneumococcal vaccination for adults. February 2015. www.cdc.gov/vaccines/hcp/patient-ed/adults/downloads/fs-pneumo-hcp.pdf. Accessed March 22, 2015.
6. Moore K. Medicare updates coverage for pneumococcal vaccinations. Getting Paid. A Family Practice Management blog. January 20, 2015. http://blogs.aafp.org/fpm/gettingpaid/entry/medicare_updates_coverage_for_pneumococcal. Accessed March 22, 2015.
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