TABLE 2.
Group C serum bactericidal titers of adults and children immunized with meningococcal polysaccharide vaccine
| Groupa | No. of subjects tested | Mean age (yr) (range) | Reciprocal titer of bactericidal antibody in serum
|
|||||
|---|---|---|---|---|---|---|---|---|
| Strain 4243 (OAc positive)
|
Strain 4335 (OAc negative)
|
|||||||
| Mean log ± SE (geometric mean)
|
Post % ≥4c | Mean log ± SE (geometric mean)
|
Post % ≥4 | |||||
| Preimmunization | Postimmunization | Preimmunization | Postimmunization | |||||
| Adults | 17 | 34 (18-45) | 0.30 ± 0.00 (2.0) | 1.24 ± 0.17 (17.2) | 76 | 0.38 ± 0.06 (2.4) | 1.58 ± 0.22 (37.9) | 76 |
| Children | ||||||||
| Group 1 | 16 | 9.5 (8.2-9.9) | 0.42 ± 0.07 (2.7) | 1.14 ± 0.19 (13.7) | 75 | 0.47 ± 0.10 (3.0) | 1.48 ± 0.22 (30.1) | 88 |
| Group 2b | 15 | 4.5 (4.1-4.9) | 0.30 ± 0.00 (2.0) | 0.36 ± 0.04 (2.3) | 13 | 0.30 ± 0.00 (2.0) | 0.67 ± 0.14 (4.7) | 47 |
a
Groups 1 and 2 were children immunized in a study in Canada (29). Bactericidal titers were not obtained for individual sera from children in groups 3 and 4 because of insufficient quantities.
b
Children in group 2 had lower geometric mean bactericidal antibody responses than did the adults (P < 0.002) or children in group 1 (P < 0.004) for both the OAc-positive and OAc-negative strains.
c
Percentage of individuals with postimmune bactericidal titers of ≥1:4.