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Vaccines for preventing pneumococcal infection in adults

  • Review
  • Intervention

Authors


Abstract

Background

Diseases caused by Streptococcus pneumoniae (S. pneumoniae) continue to cause substantial morbidity and mortality globally. Whilst pneumococcal polysaccharide vaccines (PPVs) have the potential to prevent disease and death, the degree of protection afforded against various clinical endpoints and within different populations is uncertain.

Objectives

To assess the efficacy and effectiveness of PPVs in preventing pneumococcal disease or death in adults. We did not assess adverse events.

Search methods

We searched CENTRAL 2012, Issue 6, MEDLINE (January 1966 to June Week 2, 2012) and EMBASE (1974 to June 2012).

Selection criteria

We considered randomised controlled trials (RCTs) in adults, provided the study outcome met the definition of the outcome considered in the review. We also considered non-RCTs in adults, where the study assessed PPV effectiveness against culture-confirmed invasive pneumococcal disease (IPD), provided the study controlled for important confounding factors.

Data collection and analysis

Two review authors assessed trial quality of RCTs and three review authors extracted the data. We estimated odds ratios (ORs) and 95% confidence intervals (CIs) using a random-effects model. Two review authors assessed study quality and extracted data for non-RCTs. We calculated ORs and 95% CIs using a random-effects model following the conversion of each study outcome to a log OR and standard error (SE).

Main results

Twenty-five studies met our inclusion criteria (18 RCTs involving 64,852 participants and seven non-RCTs involving 62,294 participants). Meta-analysis of the RCTs found strong evidence of PPV efficacy against IPD with no statistical heterogeneity (OR 0.26, 95% CI 0.14 to 0.45; random-effects model, I2 statistic = 0%). There was efficacy against all-cause pneumonia in low-income (OR 0.54, 95% CI 0.43 to 0.67, I2 statistic = 19%) but not high-income countries in either the general population (OR 0.71, 95% CI 0.45 to 1.12, I2 statistic = 93%) or in adults with chronic illness (OR 0.93, 95% CI 0.73 to 1.19, I2 statistic = 10%). PPV was not associated with substantial reductions in all-cause mortality (OR 0.90, 95% CI 0.74 to 1.09; random-effects model, I2 statistic = 69%). Vaccine efficacy against primary outcomes appeared poorer in adults with chronic illness. Non-RCTs provided evidence for protection against IPD in populations for whom the vaccine is currently utilised (OR 0.48, 95% CI 0.37 to 0.61; random-effects model, I2 statistic = 31%). This review did not consider adverse events as it was outside the scope of the review.

Authors' conclusions

This meta-analysis provides evidence supporting the recommendation for PPV to prevent IPD in adults. The evidence from RCTs is less clear with respect to adults with chronic illness. This might be because of lack of effect or lack of power in the studies. The meta-analysis does not provide evidence to support the routine use of PPV to prevent all-cause pneumonia or mortality.

Plain language summary

Vaccination for preventing pneumococcal infection in adults

Streptococcus pneumoniae (S. pneumoniae) is responsible for a considerable burden of illness and death in adults worldwide, usually from pneumonia and less often from invasive pneumococcal disease. Vaccination (using pneumococcal polysaccharide vaccines) might reduce such illness and death. This updated review included 18 randomised controlled trials involving 64,901 participants and seven non-randomised controlled trials involving 62,294 participants (the latter contributing outcomes for culture-confirmed invasive pneumococcal disease only).

We found consistently strong evidence that the vaccine is effective in preventing the rarer outcome of invasive pneumococcal disease. Evidence from the included studies indicates vaccination might not afford as much protection in adults with chronic illness as it does for healthy adults. The available evidence does not demonstrate that pneumococcal polysaccharide vaccines prevent pneumonia (of all causes) or mortality in adults. This review did not consider adverse events as it was outside the scope of the study.

Streszczenie prostym językiem

Szczepienia w zapobieganiu infekcjom pneumokokowym u dorosłych

Streptococcus pneumoniae (S. pneumoniae) jest odpowiedzialny za wywoływanie wielu chorób oraz zgonów wśród dorosłych na całym świecie, najczęściej zapalenia płuc oraz rzadziej inwazyjnej choroby pneumokokowej. Szczepienia (stosowanie polisachardowej szczepionki przeciwko pneumokokom) mogą zmniejszyć liczbę zakażeń oraz zgonów. Aktualizacja przeglądu obejmuje 18 badań klinicznych z randomizacją, w których udział wzięło 64 901 uczestników oraz 7 badań bez randomizacji, w których udział wzięło 62 294 uczestników (w tych ostatnich badań wykorzystano jedynie wyniki dotyczące potwierdzenia inwazyjnej choroby pneumokokowej).

Odnaleziono mocne dane potwierdzające skuteczność szczepionki w zapobieganiu rzadziej występującym przypadkom inwazyjnej choroby pneumokokowej. Dane pochodzące z włączonych badań wskazują, iż szczepienia mogą nie zapewniać tak dobrej ochrony wśród dorosłych z chorobami przewlekłymi jak w przypadku zdrowych dorosłych. Dostępne dane nie wskazują, aby polisacharydowa szczepionka przeciwko pneumokokom zapobiegała zapaleniu płuc (z wszystkich przyczyn) lub zgonom wśród osób dorosłych. W niniejszym przeglądzie nie analizowano działań niepożądanych, gdyż nie było to celem tego badania.

Uwagi do tłumaczenia

Tłumaczenie: Magdalena Koperny, redakcja: Małgorzata Bała

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