Prevalence of HBV in Pregnant Women Attending Antenatal Care in Tanzania A Survey on the Prevalence of HBsAg in Pregnant Women in the Region of Mwanza, Tanzania

Worldwide, more than 2 billion people are infected with hepatitis B virus (HBV). Of these, 240 million are chronic carriers of HBV and are at risk of death from acute fulminant liver disease, liver cirrhosis or hepatocellular carcinoma (HCC). The World Health Organization (WHO) has stated that the prevalence of hepatitis B is highest in sub-Saharan Africa and East Asia and estimates that between 5-10% of the adult population are chronically infected. Currently, several drugs have been approved in industrialized countries for treating chronic HBV infection and these follow established guidelines from professional medical organizations. Antiviral treatment of chronic hepatitis B infection significantly delays the progression of cirrhosis, reduces the incidence of HCC and improves long-term survival. However, in many resource-constrained settings, including Tanzania, the implementation of this treatment has not yet occurred.

The lack of treatment opportunities in resource-constrained settings means that the prevention of HBV infection is crucial. In countries with high HBV prevalence, most HBV transmission occurs during childhood.

In Tanzania, the prevalence of acute or chronic HBV infection (as defined by a positive hepatitis B surface antigen, HBsAg, test) among blood donors or adults in Dar es Salaam, Tanzania was found to be 8.8% and 6%, respectively. People suffering from chronic HBV have a lifelong risk of developing complications like liver cirrhosis, liver failure or hepatocellular carcinoma (HCC). Chronic hepatitis B infection is the main cause for HCC in Tanzania and there is no therapy available. There are no national recommendations or vaccination program against HBV for HCWs in Tanzania. However, in 2002,Tanzania implemented the WHO policy of general HBV vaccination for children as part of the extended program on immunization (known as EPI). According to notified data, a vaccination coverage of 84% among one year-old children was achieved in 2008 with an immunization schedule of 4, 8, 12 weeks after birth . Above 60% of the infections are acquired in the early childhood by transmission from mother to newborn. This early transmission leads to a chronic Hepatitis B infection among 90% of the infected newborn and, therefore, a vaccination at the earliest 4 weeks after birth might be too late to prevent MTCT. As a matter of fact, in Tanzania, we can estimate 1.4 million chronic Hepatitis B infections through mother-to- child transmission in early phase.

There are two interventions that could prevent MTCT:

1. Implementation of Hepatitis B Immunoglobulin (HBIg) to the child directly after birth
2. Active immunization against HBV within 24 hours after birth. The first intervention is very expensive (100€/per child) and is therefore not sustainable for the Tanzanian health system. The second intervention is cheaper and recommended by the WHO.