No evidence that pneumococcal vaccines protect the elderly from pneumonia or death in more developed countries

Watson, Lorna MRCP, MFPHM

Information and Statistics Division; Edinburgh

Abstracted from:Mangtani P, Cutts F, Hall AJ. Efficacy of polysaccharide pneumococcal vaccine in adults in more developed countries: the state of the evidence. Lancet Infect Dis 2003; 3: 71-78 .

Sources of funding: PM was funded by the Wellcome Trust through a project grant.

Correspondence to: P Mangtani, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1 E7H, UK. Tel +44 (0) 20 7927 2057; fax +44 (0) 20 7636 8739. Email: [email protected]

Abstract provided by Bazian Ltd, London

Evidence-based Healthcare 7(3):p 145-147, September 2003.

BACKGROUND

The polysaccharide pneumococcal vaccine has been introduced into the UK vaccination programme for the elderly to help prevent pneumococcal pneumonia and septicaemia, and death. Trials examining the effectiveness of the vaccine have been inconclusive and previous meta-analyses have not accounted for the heterogeneity of included studies. In particular, previous meta-analyses have included studies from both developed and developing countries, in which incidence of pneumonia varies a great deal.

OBJECTIVE

To assess the effectiveness of the pneumococcal vaccine in reducing pneumonia, septicaemia and death among the elderly in developed countries.

SEARCH STRATEGY

All available years of MEDLINE and PubMed were searched for 'all available years' (search data not specified), as were reference lists and books.

INCLUSION/EXCLUSION CRITERIA

Papers were included if they were randomised controlled trials, which addressed the question of effectiveness of vaccine in the elderly in developed countries, and there was at least an abstract in English. Meta-analyses and observational studies were also included but not combined with the trial data.

DATA ANALYSIS

Systematic review with narrative synthesis.

MAIN OUTCOMES

Pneumonia, septicaemia and death.

MAIN RESULTS

Restriction of inclusion to the three meta-analyses of trials among the elderly in developed countries found no evidence of effectiveness of the vaccine against pneumococcal pneumonia (vaccine efficacy −16 to +12%; all 95% confidence intervals included zero); against bacteraemia (vaccine efficacy 42 to 47%; all 95% confidence intervals include zero); or against death (vaccine efficacy 7 to 31%; 95% confidence intervals included zero). Most of the observational studies gave estimates of vaccine efficacy against bacteraemia of 60 to 80% (confidence intervals not reported).

AUTHORS' CONCLUSIONS

The effectiveness of pneumococcal vaccines in more developed countries cannot be extrapolated from meta-analyses including data from different populations when there is significant heterogeneity among trials. The absence of a specific diagnostic test for pneumococcal pneumonia also hampers interpretation of results. There may be a significant protective effect against bacteraemia but the evidence is weak. No effect has been shown in reducing deaths.