Pierre Chauvin, MD, PhD, DSc, Research team on social determinants of health and utilization of care, National Institute of Health and Medical Research, INSERM U444, Faculté Saint-Antoine, 27 rue Chaligny, Paris Cedex 12, 75571, France, 33144738460, pierre.chauvin@u444.jussieu.fr, Daniel K. Ekra, MD MPH, Epidemiology and public health surveillance of communicable diseases, National Institute of Public Hygiene, PO Box V14, Abidjan, Ivory Coast, Fabienne Bazin, PhD, Research team on social determinants of health and utilization of care, INSERM U444, 27 rue Chaligny, Paris, 75012, France, and Stanley A. Plotkin, MD PhD, University of Pennsylvania, 4650 Wismer Road, Doylestown, PA PA 18901.

Background: In most of sub-Saharan Africa countries, the burden of vertical and early childhood transmission of hepatitis B virus (HBV) is not documented; especially because only HBsAg screening data are available, either routinely (e.g. among blood donors) or in specific prevalence studies. Methods: We have run a cohort study of 4774 pregnant women living in Abidjan, Côte d'Ivoire, included between 01/02/2001 and 01/09/2002. All of them had blood drawn during the 3rd trimester of pregnancy and had a complete serological HBV test 6 weeks after delivery. All HBsAg+ mothers' pre-delivery sera were tested retrospectively for HBV status. Results: 7.8% of mothers were HBsAg+ (95%CI = [7.0-8.5]), of whom 14.3% were also HBeAg+ (95%CI = [10.9-18.3]). Altogether, 1.0% of mothers were diagnosed as highly infectious HBV carriers (95%CI = [0.74-1.33]). Assuming usually estimated transmission rates, we estimated that the annual incidence of chronic carriage due to vertical transmission would be 970/100,000 births. Among HBsAg+ mothers, concordance of HBeAg status before and after pregnancy was excellent (Kappa coefficient = 0.87) but 16.7% of the pre-delivery HBeAg+ /HBsAg+ subjects were found HBeAg- / HBsAg+ 6 weeks after delivery (95%CI = [5.6-34.7]); suggesting that a noticeable proportion of HBV replicating pregnant women are found to be HBeAg- after delivery. Conclusion: According to the thresholds used to define worldwide prevalence areas, Abidjan (Côte d'Ivoire) may be classified as an intermediate prevalence area. However, we estimated that a significant proportion of newborns could become chronic carriers due to vertical transmission.

Learning Objectives: At the conclusion of the session, the participant (learner) in this session will be able to

1.List the different options available to integrate VHB vaccination into expanded programs of immunization in Sub-saharian Africa 2.Know the epidemiological situation and discuss the strength and limitation of existing data on VHB prevalence in Sub-saharian Africa 3.Discuss the new perspectives open by accurate data recently collected among a urban population of pregnant women in Abidjan, Côte d'Ivoire
• Know how to estimate the burden of vertical transmission in VHB chronic carriage prevalence from available seroprevalence data.

Keywords: Hepatitis B, Maternal and Child Health

Presenting author's disclosure statement:
I do not have any significant financial interest/arrangement or affiliation with any organization/institution whose products or services are being discussed in this session.