The effects of the 23-valent pneumococcal polysaccharide vaccine in nursing home residents has been assessed in a double blind, randomised and placebo controlled trial conducted in Japan.

The study involved 1006 nursing home residents who were randomised to either 23-valent pneumococcal polysaccharide vaccine (n=502) or placebo (n=504). The primary end points were the incidence of all cause pneumonia and pneumococcal pneumonia. Secondary end points were deaths from pneumococcal pneumonia, all cause pneumonia, and other causes. The following findings were reported:

• Pneumonia occurred in 63 (12.5%) participants in the vaccine group and 104 (20.6%) in the placebo group.

• Pneumococcal pneumonia was diagnosed in 14 (2.8%) participants in the vaccine group and 37 (7.3%) in the placebo group (P<0.001).

• All cause pneumonia and pneumococcal pneumonia were significantly more frequent in the placebo group than in the vaccine group: incidence per 1000 person years 55 v 91 (P<0.0006) and 12 vs. 32 (P<0.001), respectively.

• Death from pneumococcal pneumonia was significantly higher in the placebo group than in the vaccine group (35.1% (13/37) vs. 0% (0/14), P<0.01).

• The death rate from all cause pneumonia (vaccine group 20.6% (13/63) vs. placebo group 25.0% (26/104), p = 0.5) and from other causes (vaccine group 17.7% (89/502) vs. placebo group (80/504) 15.9%, p = 0.4) did not differ between the two study groups.

The researchers conclude “the 23-valent pneumococcal polysaccharide vaccine prevented pneumococcal pneumonia and reduced mortality from pneumococcal pneumonia in nursing home residents.”

An accompanying editorial notes that this is the first trial of this type for many years, and the first to show that this vaccine protects against all cause pneumonia and pneumococcal pneumonia in older adults. However, it is noted that despite these findings, this did not translate into a reduction in all cause mortality and the overall rate of death did not differ significantly between the vaccine group and the control group. The authors of the editorial stress that “the limitations of the study such as the classification and causes of pneumonia, make it unlikely that the debate about vaccine efficacy against non-bacteraemic pneumonia in older adults will be quelled.” In the meantime, they add that existing evidence strongly supports immunising elderly people living in nursing homes, but the evidence for those living at home or those with chronic illness remains contentious.