Rubella virus infections and immune status among pregnant women before the introduction of rubella vaccine in Amhara Regional State, Ethiopia.

Background: Rubella and its associated congenital anomalies have been greatly reduced in most developed countries through use of the rubella vaccine. However, the magnitude of the problem is underestimated and there are no well-established rubella/congenital rubella syndrome prevention and control strategies in many developing countries, including Ethiopia. The aim of this study was to determine the prevalence of rubella virus infections among pregnant women and their immune status before the introduction of rubella vaccine in Amhara Regional State, Ethiopia.

Methods: A prospective cross-sectional study was conducted among pregnant women in Dessie, Felege-Hiwot, and University of Gondar referral hospitals, from December 2015 to February 2017. After obtaining written informed consent, socio-demographic data, reproductive history, clinical manifestations, and the possible risk factors for rubella virus infections were collected using a structured questionnaire. The laboratory analysis of rubella-specific antibodies was done using an enzyme-linked immunoassay method on venous blood samples. Data were entered and analyzed using IBM SPSS Statistics version 20. Binary logistic regression was used to determine the strength of association between the dependent variables and covariates.

Results: A total of 600 pregnant women were included in the study. Their mean age was 26.4±5years (range 16-40 years). The overall seroprevalence of rubella infection was 89%. Of the total study participants, 9.5% were positive for rubella-specific IgM antibody, which indicates acute/recent rubella virus infection. In contrast, 79.5% of them had protective levels of rubella-specific IgG antibody and were immune as a result of previous wild-type rubella infection. However, 11% of the pregnant women were negative for both rubella-specific antibodies; these women represent the susceptible group.

Conclusions: A large number of pregnant women had acute/recent rubella virus infections at the time of data collection, indicating that the virus is endemic in the study area. More than a tenth of pregnant women were found to be susceptible to acquiring the infection in future pregnancies, with the possible risk of rubella-associated congenital anomalies. Hence screening of all women of child-bearing age before conception and during pregnancy might reduce the devastating effects of the virus on the developing fetus.