Efficacy of pneumococcal vaccination

With respect to the efficacy of pneumococcal vaccination:

• in adults:
  • polysaccharide pneumococcal vaccines (PPV) do not appear to reduce the incidence of pneumonia or death in adults with or without chronic illness, or in the elderly (55 years and above) (1)
    • evidence suggests that pneumococcal vaccines are effective in the reducing the incidence of the more specific outcome, invasive pneumococcal disease, among adults and the immunocompetent elderly (55 years and above). However surveillance data suggest that infection rates vary widely between and also within countries, but a typical figure in developed countries is 0.01%, or 10 per 100,000 per year. If an efficacy of 50% is assumed then this corresponds to a number-needed-to-treat (NNT) of 20,000 vaccinations per infection avoided, and perhaps 50,000 vaccinations per death avoided
  • a more recent meta-analysis concluded that pneumococcal vaccination is not effective for preventing pneumonia, bacteraemia, bronchitis or mortality in adults (2)
• in children under 2 years of age (3):
  • pneumococcal vaccination is effective in reducing the incidence of invasive pneumococcal disease from all serotypes but exerts a greater effect in reducing vaccine serotypes invasive pneumococcal disease
• in patients with sickle cell disease (4):
  • a systematic review recommended that conjugate pneumococcal vaccines are used in people with sickle cell disease
• as a measure to prevent recurrent acute otitis media (AOM) (5,6):
  • a systematic review concluded that use of pneumococcal polysaccharide and conjugate vaccination for this specific indication is not yet recommended (5)
  • a more recent systematic reveiw regarding pneumococcal conjugate vaccines concluded that based on current evidence of the effectiveness of pneumococcal conjugate vaccines for the prevention of AOM, the currently licensed 7-valent PCV administered during infancy has marginal beneficial effects
  • administering PCV7 in older children with a history of AOM appears to have no benefit in preventing further episodes.

Notes:

• the Green book chapter states that
  • "...Most healthy adults develop a good antibody response to a single dose of PPV by the third week following immunisation. Antibody response may be reduced in those with immunological impairment and those with an absent or dysfunctional spleen. Children younger than two years of age show poor antibody responses to immunisation with PPV. It is difficult to reach firm conclusions about the effectiveness of PPV, but overall efficacy in preventing pneumococcal bacteraemia is probably 50 to 70%... Current evidence suggests that PPV is not effective in protecting against non-bacteraemic pneumococcal pneumonia. It does not prevent otitis media or exacerbations of chronic bronchitis. The vaccine is relatively ineffective in patients with multiple myeloma, Hodgkin's and non-Hodgkin's lymphoma (especially during treatment) and chronic alcoholism...The vaccine does not protect against pneumococcal infection due to capsular types not contained in the vaccine, but the 23 types included account for about 96% of the pneumococcal isolates that cause serious infection in the UK..."

Reference:

• 1. Dear K, Holden J, Andrews R, Tatham D. Vaccines for preventing pneumococcal infection in adults. Cochrane Database Syst Rev. 2003;(4):CD000422. Review.
• 2. Huss A et al. Efficacy of pneumococcal vaccination in adults: a meta-analysis.CMAJ. 2009 Jan 6;180(1):48-58.
• 3. Lucero MG et al. Pneumococcal conjugate vaccines for preventing vaccine-type invasive pneumococcal disease and pneumonia with consolidation on x-ray in children under two years of age. Cochrane Database Syst Rev. 2004 Oct 18;(4):CD004977
• 4. Davies EG et al. Pneumococcal vaccines for sickle cell disease. Cochrane Database Syst Rev. 2004;(1):CD003885.
• 5. Straetemans M et al. Pneumococcal vaccines for preventing otitis media. Cochrane Database Syst Rev. 2004;(1):CD00148
• 6. Jansen AG et al.Pneumococcal conjugate vaccines for preventing otitis media. Cochrane Database Syst Rev. 2009 Apr 15;(2):CD001480.
• 7. Immunisation Against Infectious Disease - "The Green Book".Chapter 25 Pneumococcal (April 2019)