Table 5.
Univariate logistic regression analysis of variables for diphtheria immunity
| Characteristics | Immunitya (n = 1423) | Susceptibility (n = 802) | OR (95%CI) | p-Valuec |
|---|---|---|---|---|
| Gender | ||||
| Male (Ref) | 470 (64.1%) | 263 (35.9%) | - | - |
| Female | 953 (63.9%) | 539 (36.1%) | 1.0 (0.8-1.2) | 0.91 |
| Age groups | ||||
| 0-5 | 56 (68.3%) | 26 (31.7%) | 1.6 (0.9-2.9) | 0.08 |
| 6-10 | 155 (66.5%) | 78 (33.5%) | 1.8 (1,2-2,8) | <0.01 |
| 11-20 | 298 (65.2%) | 159 (34.8%) | 1.9 (1.3-2.8) | <0.01 |
| 21-30 | 251 (55.9%) | 198 (44.1%) | 2.8 (1.2-4.1) | <0.01 |
| 31-40 | 225 (59.5%) | 153 (40.5%) | 2.4 (1.6-3.6) | <0.001 |
| 41-50 | 155 (64.9%) | 84 (35.1%) | 1.9(1.2-2.9) | <0.001 |
| 51-60 | 129 (67.9%) | 61 (32.1%) | 1.7 (1.1-2.7) | 0.02 |
| >61 (Ref) | 154 (78.2%) | 43 (21.8%) | - | - |
| Ethnicity | ||||
| Kinh (Ref) | 459 (70.2%) | 195 (29.8%) | - | - |
| Ba Na | 329 (72.3%) | 126 (27.7%) | 0,9 (0.7-1.2) | 0.44 |
| So Dang | 322 (59.0%) | 224 (41.0%) | 1.6 (1.3-2.1) | <0.001 |
| Others | 313 (54.9%) | 257 (45.1%) | 1.9 (1.5-2.3) | <0.001 |
| Residence | ||||
| Rural (Ref) | 912 (61.4%) | 573 (38.6%) | - | - |
| Urban | 511 (69.1%) | 229 (30.9%) | 0.7 (0.6-0.9) | <0.001 |
| Education | ||||
| Illiteracy (Ref) | 132 (66.0%) | 68 (34.0%) | - | - |
| No school | 59 (66.3%) | 30 (33.7%) | 1.0 (0.6-1.7) | 0.96 |
| Primary school | 525 (60.8%) | 339 (39.2%) | 1,2 (0.9-1.7) | 0.17 |
| Secondary school | 517 (66.9%) | 256 (33.1%) | 0.9 (0.7-1.3) | 0.81 |
| High school | 126 (56.8%) | 96 (43.2%) | 1.5 (1.0-2.2) | 0.52 |
| College/University | 64 (83.1%) | 13 (16.9%) | 0.4 (0.2-0.7) | 0.06 |
| Occupation | ||||
| Farmer/worker (Ref) | 784(60.8%) | 506 (39.2%) | - | - |
| Pupil/Student | 460 (67.8%) | 218 (32.2%) | 0.7 (0.6-0.9) | <0.05 |
| Employer | 88 (76.5%) | 27 (23.5%) | 0.5 (0.3-0.7) | <0.05 |
| Self-employed/unemployment | 91 (64.1%) | 51 (35.9%) | 0.8 (0.6-1.2) | 0.44 |
| History of diphtheria vaccination during last 10 years | ||||
| Yes (Ref) | 553 (83.8%) | 107 (16.2%) | - | - |
| No | 737 (54.8%) | 609 (45.2%) | 4.3 (3.4-5.4) | <0.0001 |
| Unknown | 133 (60.7%) | 86 (39.3%) | 3.3 (2.4-4.7) | <0.0001 |
aImmunity: IgG antibody titre against diphtheria toxin ≥ 0.01 IU/mL.
bSusceptibility: IgG titre against diphtheria toxin < 0.01 IU/mL.
cChi-Square test