Hepatitis B virus infection among antenatal clinic attendees at the Muhimbili National Hospital, seroprevalence and associated factors

Abstract

Background: Hepatitis B virus (HBV) infection is a serious public health problem in sub-Saharan Africa. Vertical transmission is one of the modes of transmission. The risk of transmission increases if the mother is hepatitis B surface antigen (HBsAg) positive and more so if also hepatitis B envelope antigen (HBeAg) positive. Current magnitude of HBV infection at Muhimbili National Hospital MNH is not known, and could be on the increase due to the HIV epidemic, since the two have a shared mode of transmission. Objectives: To determine the seroprevalence of HBV infection and associated factors among pregnant women attending Antenatal Clinic at Muhimbili National Hospital. Methodology: This was a cross-sectional study conducted at the Antenatal Clinic, Muhimbili National Hospital between 31stAugust and 22nd September 2010. Data including socio-demographic (age, residence, marital status, education level, occupation) sexual history (number of life-time sexual partners), obstetrics (parity) and history of blood transfusion were collected using a structured questionnaire. Blood specimen was collected for detection of HBsAg, HBeAg, IgM antibodies to hepatitis B core antigen (Anti-HBc), antibodies to hepatitis B surface antigen (anti-HBs) and HIV antibodies. Ethical clearance and informed consent were obtained prior to the enrolment in the study. Data were analyzed using the SPSS version 16.0. Fisher’s exact tests were used for analysis. A p-value of <0.05 was regarded as statistically significant. vii Results: A total of 310 pregnant women were enrolled in the study. Their overall mean (SD) age was 28.5 (5.4) years. Majority of the women were from the Kinondoni Municipality, married and had primary education. Ninety-six (31.0%) of the women were primigravidae. Of the 310 women 12 (3.9%) tested positive for HBsAg. Of the 12 women with positive HBsAg, none had detectable anti-HBs antibodies. None had IgM HBcAb, excluding acute HBV infection. In addition, all these women tested negative for HBeAg. The prevalence of HIV infection was 9.7%. Three of 12 (25%) women had HBV and HIV co-infection. There were no significant differences between those who tested positive and those who tested negative to HBsAg with respect to age, residence, marital status, education level, occupation and parity. Similarly, there were no statistically significant differences noted between the two groups with regard to number of life-time sexual partners, HIV serostatus and history of blood transfusion. Conclusion and Recommendation The seroprevalence of 3.9% HBsAg was of moderate severity according to WHO. This finding would suggest for the introduction of routine screening for HBV to all pregnant women during the antenatal period, and that “at birth dose” vaccination is given to new born babies of mothers found to be HBsAg positive so as to reduce and prevent the spread of infection. However more data is required from larger studies to support the findings so that ultimately this can be recommended as a policy