Seroprevalence of rubella virus IgG in pregnant women in Harare, Zimbabwe.

Abstract

Rubella is an infectious disease caused by a virus belonging to the family Togaviridae.1 The virus is mainly transmitted from human to human by direct contact with infected bodily fluids or respiratory droplet secretions from infected people.1 In pregnant women, primary infection with the virus may cause congenital rubella syndrome (CRS), often accompanied by miscarriage, stillbirth and/or birth defects in infants.2,3 It is therefore strongly recommended by the World Health Organization that serological surveys on rubella virus infection in women of childbearing age be done.4 In Zimbabwe, no studies evaluating the seroprevalence of rubella virus in women of childbearing age have previously been conducted. Furthermore, there is no national public health policy on rubella screening or immunization in Zimbabwe. The objective of this study was to evaluate the seroprevalence of rubella virus IgG antibodies in pregnant women attending antenatal clinics in Harare, Zimbabwe. The study protocol was reviewed and approved by the Joint Parirenyatwa Hospital and University of Zimbabwe’s College of Health Sciences Research Committee (JREC ref: IRB 123). Pregnant women presenting at two antenatal clinics in Harare, Zimbabwe, were included in the study. The study sites were Rutsanana and Rujeko polyclinics that serve high-density areas of the Harare City. A sample size of 51 women was recruited. After completion of informed consent, the women were interviewed using a questionnaire, and data on their demographic, socio-economic and obstetric variables were captured. Any pregnant woman resident in Harare, with an age between 18 and 50 years who consented to participate was included in the study. An aliquot of venous blood was collected from each woman on site and transported on ice to the University of Zimbabwe, Department of Medical Microbiology, Laboratory for Immunological Assays. The sera were tested for rubella IgG antibodies using the anti-rubella virus IgG ELISA kit (Siemens, Germany) according to manufacturer’s instructions. Results were read using the microwell reader at 450 nm. The kit had positive and negative controls which were run with the samples as part of quality control. Calculations of IgG results were done by software package KC4 and transferred to the Dade Behring Excel package that validated the assay by calculating lower and upper limits for the optometric densities. Data from the study were entered into an Excel spreadsheet and imported to the statistical package (STATA 11.0) for analysis.