. 2014 Sep 3;92(11):782–789. doi: 10.2471/BLT.13.133413

Table 3. Influence of parity and being born before 1984 on hepatitis B surface antigen carriage by pregnant women, Hong Kong Special Administrative Region, China, 1998–2011.

Women’s year of birth	Prevalence of HBsAg carriage (%)		Likelihood of HBsAg carriage by a nullipara, OR (95% CI)
Women’s year of birth	Nulliparas	Multiparas	Likelihood of HBsAg carriage by a nullipara, OR (95% CI)
All	7.3	8.2	0.879 (0.743–1.038)
≥ 1984	5.6	6.7	0.824 (0.591–1.148)
< 1984	8.2	8.8	0.923 (0.760–1.120)
OR (95% CI)^a	0.655 (0.553–0.799)	0.745 (0.532–1.044)	NA

CI: confidence interval; HBsAg: hepatitis B surface antigen; NA: not applicable; OR: odds ratio.

^a Likelihood of hepatitis B surface antigen carriage by a woman born in or after 1984, when neonatal vaccination against the hepatitis B virus became available.