Table 1. Carriage of hepatitis B surface antigen by pregnant women, by age at parturition and year of their birth, Hong Kong Special Administrative Region, China, 1998–2011.
| Age at parturition (years) | No. of women |
Prevalence of HBsAg carriage in women, no. (%) |
Likelihood of HBsAg carriage by a woman born in or after 1984, OR (95% CI) | |||
|---|---|---|---|---|---|---|
| born in or after 1984a | born before 1984a | born in or after 1984a | born before 1984a | |||
| ≤ 16 | 98 | 31 | 1 (1.0) | 2 (6.5) | 0.149 (0.013–1.708) | |
| 17 | 145 | 84 | 2 (1.4) | 4 (4.8) | 0.280 (0.050–1.561) | |
| 18 | 248 | 185 | 12 (4.8) | 18 (9.7) | 0.472 (0.221–1.006) | |
| 19 | 301 | 378 | 17 (5.6) | 27 (7.1) | 0.778 (0.416–1.456) | |
| 20 | 406 | 498 | 17 (4.2) | 47 (9.4) | 0.419 (0.237–0.742) | |
| 21 | 409 | 644 | 22 (5.4) | 46 (7.1) | 0.739 (0.438–1.248) | |
| 22 | 500 | 882 | 28 (5.6) | 82 (9.3) | 0.579 (0.371–0.902) | |
| 23 | 546 | 1162 | 36 (6.6) | 108 (9.3) | 0.689 (0.466–1.019) | |
| 24 | 545 | 1405 | 39 (7.2) | 116 (8.3) | 0.856 (0.587–1.249) | |
| 25 | 491 | 1850 | 41 (8.4) | 145 (7.8) | 1.071 (0.746–1.539) | |
| Total | 3689 | 7119 | 215 (5.8) | 595 (8.4) | 0.679 (0.578–0.797) | |
CI: confidence interval; HBsAg: hepatitis B surface antigen; OR: odds ratio.
a Neonatal vaccination against the hepatitis B virus became available in 1984.