Rubella virus immunization status in preconception period among Chinese women of reproductive age: A nation-wide, cross-sectional study

Objective: Population-based studies on sero-epidemiology of Rubella in women before conception are lacking. The aim of this study was to investigate the sero-prevalence of Rubella in a nationwide survey among Chinese women planning to get pregnant within six months.

Methods: This population-based, cross-sectional, sero-survey of Rubella virus infection was a part of the National Free Preconception Health Examination Project covering all 31 provinces in Mainland China. Women intending to get pregnant within six months was enrolled between 2010 and 12. Information on demographic characteristics (age, residence status, race, education and occupation) and vaccination history was obtained by interviews. Rubella virus IgG sero-positivity was determined using venous blood samples.

Results: Of 2,120,131 women recruited to the study, Rubella virus IgG serology was available in 1,974,188 (99.3%). Participating women were of young age (median=28years), mostly engaged in agricultural activities (78%), and the majority (90%) had high school education or lower. The overall prevalence of Rubella virus IgG sero-positivity was 58.4% (1,161,129); geographical variation ranged from 92.5% in Jilin to 20.1% in Qinghai and 0.0% in Tibet. Only 4.6% (n=91,604) women reported to have had Rubella virus vaccination, and it varied from 18.6% (Guangdong) to 0.2% (Qinghai). Self-reported vaccination status did not correlate with Rubella virus IgG seropositivity.

Conclusions: Prevalence of Rubella sero-positivity is low among Chinese women of reproductive age and there are significant regional differences. Over 40% of women being susceptible to Rubella in preconception period calls for a targeted screening and vaccination strategy.