The efficacy of pneumococcal polysaccharide vaccine has had inconsistent results in systematic reviews. It now appears that the best available evidence suggests that it is ineffective (level 2 [mid-level] evidence).
Last week, DynaMed Editors saw the first systematic review of this vaccine that explicitly considered trial quality in the analysis (CMAJ 2009 Jan 6;180(1):48 full-text). The review included 22 randomized or quasi-randomized trials of pneumococcal polysaccharide vaccine with 101,507 adults. Polysaccharide pneumococcal vaccine was associated with a reduced risk for presumptive pneumococcal pneumonia and for all-cause pneumonia in comprehensive meta-analyses. However, these meta-analyses were limited by substantial heterogeneity and there were no significant differences in analyses limited to higher-quality trials (i.e. trials with blinding and allocation concealment). The authors conclude that "Pneumococcal vaccination does not appear to be effective in preventing pneumonia, even in populations for whom the vaccine is currently recommended."
In 2008, a Cochrane review evaluated 15 randomized and 7 non-randomized trials with 110,950 adults (Cochrane Database Syst Rev 2008 Jan 23;(1):CD000422). In randomized trials, pneumococcal polysaccharide vaccine was associated with a decreased risk for invasive pneumococcal disease (NNT 371) and for all-cause pneumonia (NNT 59). However, most trials had unclear or inadequate allocation concealment which is a major quality criterion considered in Cochrane reviews.
CDC/ACIP/AAFP/ACP/ACOG all currently recommend pneumococcal vaccination for persons over 65 years old, smokers, residents of long-term care facilities or persons with any of the following conditions: chronic lung disease (including asthma), chronic cardiovascular diseases, diabetes mellitus, chronic liver diseases, chronic alcoholism, chronic renal failure or nephrotic syndrome, functional or anatomic asplenia, impaired immune function, cochlear implants, and cerebrospinal fluid leaks. The USPSTF has stopped updating its recommendations for immunizations for adults.
For more information, see the DynaMed topic Pneumococcal Vaccine.
