TABLE 2.
Geometric mean serogroup C-specific IgG antibody concentrations measured using O-acetylated and de-O-acetylated serogroup C polysaccharide assays and GMAIs before and after administration of MCC vaccine and before and after a challenge dose of A/C polysaccharide vaccine (10-μg dose) according to study groupa
| Assay | Study group | Prevaccination
|
1 mo post-MCC
|
Prechallenge
|
1 mo postchallenge
|
||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| n | n (%) with Oac+ <0.6 | GMC or GMAI (95% CI) | n | n (%) with Oac+ <0.6 | GMC or GMAI (95% CI) | n | n (%) with Oac+ <0.6 | GMC or GMAI (95% CI) | n | n (%) with Oac+ <0.6 | GMC or GMAI (95% CI) | ||
| Oac− | 1 | 181 | NA | 0.3 (0.2-0.3) | 183 | NA | 24.0 (21.1-27.3) | 147 | NA | 1.0 (0.8-1.1) | 166 | NA | 13.5 (11.6-15.6) |
| 2 | 187 | NA | 0.3 (0.2-0.3) | 188 | NA | 15.9 (14.5-17.3) | 149 | NA | 1.5 (1.3-1.8) | 158 | NA | 10.2 (8.7-11.9) | |
| 3 | 172 | NA | 0.2 (0.2-0.3) | 173 | NA | 28.5 (26.0-31.3) | 141 | NA | 1.8 (1.6-2.1) | 142 | NA | 11.1 (9.7-12.8) | |
| Oac+ | 1 | 181 | NA | 0.2 (0.2-0.3) | 183 | NA | 8.3 (7.3-9.5) | 147 | NA | 0.8 (0.7-0.9) | 166 | NA | 25.4 (21.4-30.3) |
| 2 | 187 | NA | 0.2 (0.2-0.2) | 188 | NA | 8.7 (7.9-9.7) | 149 | NA | 1.3 (1.1-1.5) | 158 | NA | 17.5 (14.7-20.8) | |
| 3 | 172 | NA | 0.2 (0.2-0.2) | 173 | NA | 13.3 (12.0-14.7) | 141 | NA | 1.4 (1.2-1.6) | 142 | NA | 18.1 (15.2-21.6) | |
| GMAI | 1 | 177 | 137 (77.4) | 91.1 (75.9-109.5) | 180 | 4 (2.2) | 63.3 (60.6-66.1) | 105 | 22 (21.0) | 111.8 (101.8-122.9) | 161 | 3 (1.9) | 186.9 (174.2-200.6) |
| 2 | 184 | 139 (75.5) | 106.8 (92.3-123.6) | 185 | 0 (0) | 83.4 (79.0-88.0) | 131 | 16 (12.2) | 114.2 (105.5-123.6) | 150 | 0 (0) | 162.3 (151.9-173.4) | |
| 3 | 173 | 138 (79.8) | 88.6 (69.7-112.5) | 170 | 0 (0) | 78.9 (75.6-82.3) | 121 | 8 (6.6) | 106.6 (99.3-114.5) | 137 | 1 (0.7) | 150.6 (141.3-160.4) | |
a
NA, Not applicable; that is, GMAI cannot be measured in subjects with serogroup C-specific IgG levels of <0.6 μg/ml.