Previous vaccination with PCV7 did not improve immune response to PPV23 in older Alaskans

Receipt of the seven-valent pneumococcal conjugate vaccine two or six months prior to receipt of the 23-valent pneumococcal polysaccharide vaccine did not yield increased immune response among Alaska Native adults.

The study was conducted on 55- to 70-year-old participants who had not previously been administered pneumococcal vaccine.

Researchers randomly assigned 28 participants to receive PPV23 alone, 29 participants to receive PPV23 two months after receiving the PCV7 and 29 participants to receive PPV23 six months after receiving PCV7 between May 2002 and February 2003.

The researchers collected serum samples and tested them for serotype-specific immunoglobulin G and for opsonophagocytic activity against serotypes 1, 4, 6B, 14 and 19F.

After one dose of either PCV7 or PPV23, the geometric mean immunoglobulin G concentrations of and the median opsonophagocytic activity titers to serotypes 4, 6B, 14 and 19F increased in all three groups. There was no difference in serotype-specific geometric mean immunoglobulin G concentrations and median opsonophagocytic activity titers between patients who had received PCV7 previously and those who had not.

There were no differences in local reactions among participants who received a single dose of either PPV23 or PCV7. Among participants who received PCV7 prior to PPV23, arm pain (P<.01), injection site redness (P=.02) and swelling (P<.01) were reported with greater frequency than in those participants who received only PPV23.

There was more injection site swelling among participants who received PPV23 two months after PCV7 than there was among participants who received PPV23 six months after PCV7 (P=.01).

Miernyk KM et al. Clin Infect Dis. 2009;49:241-248