Rubella Seropositivity and Associated Factors Among Young Female Adults in Bangladesh: A Cross-Sectional Study.

Purpose: A cross-sectional study was conducted among young female adults aged 18 to 24 years in Bangladesh to assess rubella IgG seropositivity and associated factors.

Methods: Data were collected on participants' sociodemographic and family characteristics, residency and age during 2014 Measles-Rubella campaign, and rubella vaccination history. Blood samples were collected and tested for rubella virus-specific immunoglobulin G (IgG) antibodies (rubella IgG) using chemiluminescence immunoassay.

Results: Of the 250 young female adults aged 18-24 years, 87.20% (95% CI: 83.06%-91.34%) were seropositive for rubella IgG: 89.47% among the vaccinated, 85.93% among the non-vaccinated, and 88.54% among those with unknown vaccination history. Seropositivity was not significantly associated with reported rubella vaccination history. Titer levels were significantly higher in seropositive participants without a vaccination history (Median 66.75 IU/mL; interquartile range (IQR): 42.53-98.47) than those with a history (Median 37.30 IU/mL; IQR: 29.70-65.60). Compared with those from rural locations, participants from urban locations had significantly lower odds of seropositivity (Odds Ratio 0.33; 95% CI: 0.12-0.92; p = 0.035).

Conclusion: A relatively high prevalence of rubella IgG seropositivity was detected. However, approximately one in ten participants remained susceptible to rubella infection during pregnancy and at risk of related adverse outcomes, including congenital rubella syndrome. Seropositivity was not associated with rubella vaccination history suggesting endemic transmission of the rubella virus. The low proportion of participants with a known vaccination history indicates gaps in vaccination documentation. Therefore, well-recorded vaccination histories and strengthened surveillance systems should be developed.