TABLE 3.

Immunogenicity of PPV revaccination in older adults

Study	Population	Yrs since first vaccination	Antibodies to CPs after revaccinationb
Mufson et al. (80)a	n = 15; mean age, 75 yr; community	6 yr	Mean, 1.5 FI; response less than peak after primary vaccination
Davidson et al. (33)a	n = 13; age, ≥65 yr; Alaskan natives	Mean, 7.4 yrc	22% suboptimal response compared with 12% in group <65 yrd
			50% reduction of suboptimal responses; same reduction in group <65 yr and group ≥65 yr
Musher et al. (87)	n = 8; mean age, 71 yr; veterans	6 yr	70% positive antibody reactions; increase from 58% positive reactions prior to revaccination (78% positive reactions at peak after initial vaccine)
Jackson et al. (57)	n = 65; age, 50-74 yr	Median, 6 yra	Numerically higher than levels before revaccinationf (statistically not different)
			Levels lower than separate group post-first PPV (statistically less for 1/3 serotypes)

^aWithout absorption of antibody to cell wall polysaccharide.

^bAntibody measurements taken approximately 1 month after revaccination.

^cMean of entire population; time since revaccination for subset ≥65 years not provided.

^dSuboptimal defined as <500 ng of antibody nitrogen/ml.

^eFor the entire group; mean or median since revaccination not provided for subset of older subjects studied for immunogenicity.

^fUnclear if immunogenicity data for subjects before revaccination are mutually exclusive from those for subjects after revaccination. The cohort prior to revaccination has 82 subjects, whereas the cohort after revaccination has 65 subjects.