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Ask the Experts: Revaccination with 23-valent pneumococcal vaccine

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Learn the optimal schedule for administering the 23-valent pneumococcal vaccine.

Question: Some providers are recommending the 23-valent pneumococcal vaccine (Pneumovax 23—Merck) every 5 years, whereas others are saying it is only given once. When should it be repeated and how often?

Answer: Streptococcus pneumoniae is a bacterial pathogen that affects both children and adults worldwide. Serotypes of this bacterium have an outer capsular component consisting of complex polysaccharides that are specifically pathogenic to humans.1 The aim of pneumococcal vaccination is to produce antibodies that bind to the capsule and help protect against invasive pneumococcal disease (e.g., bacteremia, meningitis, infection of other sterile sites).

Several age groups and several health conditions are risk factors that increase the risk for pneumococcal infection. The Advisory Committee on Immunization Practices (ACIP) recommends administering the polysaccharide pneumococcal vaccine to patients aged 2 to 64 years who have any of several underlying medical conditions, including chronic heart disease, chronic obstructive pulmonary disease, diabetes, asplenia, and immune suppression. In addition, all patients 65 years or older should receive a single dose of this vaccine.2 Newer recommendations by ACIP include vaccinating individuals aged 19 to 64 years who have asthma or smoke.3 The current polysaccharide pneumococcal vaccine (Pneumovax 23) protects against 23 serotypes of S. pneumoniae (serotypes 1, 2, 3, 4, 5, 6B, 7F, 8, 9N, 9V, 10A, 11A, 12F, 14, 15B, 17F, 18C, 19F, 19A, 20, 22F, 23F, and 33F).4

Vaccine efficacy and effectiveness against invasive pneumococcal disease has been demonstrated in various studies to range from approximately 50% to 90% following vaccination.2,4 However, the antibody response to all 23 serotypes may not be consistent and serotype-specific antibodies may decline after 5 to 10 years because of aging and the patient’s immune functioning.2,5 A single booster dose is therefore recommended 5 years or more after the first dose for patients 10 to 64 years of age with functional or anatomical asplenia or if they are immune suppressed. If the patient received vaccine before the age of 65, a second dose should be administered 5 or more years after the first dose. These individuals are at higher risk for invasive pneumococcal disease or are likely to have more rapid declines in protective antibody levels.2 Vaccination with polysaccharide vaccines elicits a T-cell–independent immune response; therefore, a substantial increase in antibody titers may not be observed following revaccination.2,4

Immune hyporesponsiveness, defined as a lower antibody response to subsequent doses of the same vaccine, is a controversial topic and is of potential concern when readministering polysaccharide vaccines.6 This effect may be attributable to the patient’s age at vaccination and/or the interval between doses of vaccine; however, immune hyporesponsiveness is not fully understood. One theory suggests that repeat antigentic stimulation with vaccine “exhausts” the pool of antibodies and does not adequately replenish them.7 Regardless, the clinical significance of immune hyporesponsiveness is not well defined because immune correlates of protection have not been established for this vaccine.2,6

In one study of 61 patients (mean age 69 years [range 50–82]), antibody titers to pneumococcal serotypes 1, 4, 7F, 14, 18C, and 19F were observed to increase significantly from baseline (geometric mean concentration of 19.06 vs. 6.97 mcg/mL, P < 0.0001) following initial vaccination; however, these levels declined below baseline 4 to 7 years later. A mean of 5.3 years after revaccination, antibody titers again increased significantly compared with prerevaccination levels, but the response to revaccination was significantly lower compared with after initial vaccination (geometric mean concentration of 7.47 vs. 19.06 mcg/mL, P < 0.001).8 These results suggest that immune hyporesponsiveness is present and active. In contrast, however, another study of 120 patients (mean age 71 years [range 65–88]) measuring both functional (opsonic) and total antibody levels to serotypes 4, 14, and 23F following primary vaccination or revaccination (3–5 years after a first dose) showed similar antibody responses. At 30 days after primary vaccination or revaccination, geometric mean concentrations of antibodies to all three serotypes studied and opsonophagocytic killing geometric mean antibody titers to serotypes 4 and 23F were statistically similar (P > 0.05) but higher in the primary vaccination group. This result also was observed 5 years after primary or revaccination; however, geometric mean concentrations and opsonophagocytic killing geometric mean antibody titers were slightly higher in the revaccination group.9

In light of these conflicting data, multiple revaccinations are not currently recommended by ACIP beyond the single revaccination policy described above.

Karl Hess, PharmD
Assistant Professor of Pharmacy Practice and Administration
Director, Community Pharmacy Residency Training Program
Certificate in Travel Health (CTH)
College of Pharmacy
Western University of Health Sciences

Johnny Thai
Student Pharmacist
College of Pharmacy
Western University of Health Sciences

References

  1. CDC. Pneumococcal disease. Accessed at www.cdc.gov/vaccines/pubs/pinkbook/downloads/pneumo.pdf, November 16, 2010.
  2. CDC. Prevention of pneumococcal disease: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep. 1997;46(RR-8):1–24.
  3. CDC. Updated recommendations for prevention of invasive pneumococcal disease among adults using the 23-valent pneumococcal polysaccharide vaccine (PPSV23). MMWR Morb Mortal Wkly Rep. 2010;59:1102–6.
  4. Pneumovax 23 [package insert]. Whitehouse Station, NJ: Merck; 2010.
  5. World Health Organization. 23-valent pneumococcal polysaccharide vaccine: WHO position paper. Wkly Epidemiol Rec. 2008;83:373–84.
  6. World Health Organization. Duration of protection and revaccination. Accessed at www.who.int/immunization/PPV23_Additional_summary_Duration_protection_revaccination.pdf, October 22, 2010.
  7. Bernatoniene J, Finn A. Advances in pneumococcal vaccines: advantages for infants and children. Drugs. 2005;65:229–55.
  8. Torling J, Hedlund J, Konradsen HB, Ortqvist A. Revaccination with the 23-valent pneumococcal polysaccharide vaccine in middle aged and elderly patients previously treated for pneumonia. Vaccine. 2003;22:96–103.
  9. Manoff SB, Liss C, Caulfield MJ, et al. Revaccination with a 23-valent pneumococcal polysaccharide vaccine induces elevated and persistent functional antibody responses in adults aged 65 > or = years. J Infect Dis. 2010;201:525–33.
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