Rubella Seromarkers and Determinants of Infection among Tanzanian Children and Adolescents in Prevaccination Era: Are We in the Right Track?

BACKGROUND: The World health organization advocates assessment of the burden of rubella and congenital rubella syndrome (CRS) by seroepidemiological surveys and surveillance programs in all countries without vaccination programs. Due to scarcity of data in developing countries, this study was conducted to assess the seromakers for natural rubella infection in Tanzania during prevaccination era so as to ascertain the gaps for future research and prevention strategies.

METHODS: A cross-sectional study was conducted between September and October 2014. Indirect enzyme-linked immunosorbent assay was used to detect rubella IgG and IgM antibodies. STATA version 11 was used to perform data analysis.

RESULTS: Of 723 enrolled participants, 368 (50.8%) and 94 (13%) were positive for specific IgG and IgM rubella antibodies, respectively. On multivariable logistic regression analysis, significant determinants of rubella IgG seropositivity were increase in age (odds ratios [OR]: 1.24, 95% confidence interval [CI]: 1.18-1.29, P < 0.001), low socioeconomic status (SES) (OR: 2.38, 95% CI: 1.1.23-4.50, P = 0.010), and absence of rash (OR: 4.34, 95% CI: 1.1.17-15.3, P = 0.027), while only the presence of rashes was significant determinant of rubella IgM seropositivity (OR: 2.5, 95%; 1.07-5.98, P = 0.034). Significantly higher mean IgG titers were observed in population ≥10 years (P < 0.001), those residing in urban and peri-urban areas (P < 0.001), those from employed mothers (P = 0.018), and those with no current history of fever (P = 0.018).

CONCLUSIONS: The prevalence of specific rubella IgG antibodies in Tanzania is high and is associated with increase in age, absence of rash, and low SES. Results suggest a need to reconsider upper age limit for vaccination campaigns in developing countries. Screening and vaccinating women may be cost-effective campaign to prevent CRS in developing countries.