Seroprevalence of hepatitis b infection in children less than five years of age at the university teaching hospitals - children’s hospital and Kamwala Health Centre in the vaccination era in Lusaka, Zambia

Abstract

HBV infection is a serious infection affecting the liver and causes significant morbidity and mortality in sub-Sahara Africa. While most patients with chronic hepatitis B virus infection are asymptomatic, the infection acquired during infancy or childhood accounts for a disproportionately large share of worldwide morbidity and mortality. The prevalence of hepatitis B virus infection in Africa is between five to ten percent in the adult population. The seroprevalence of this infection in Zambian children after the introduction of the hepatitis B vaccine is not known. This was a cross sectional study done in children below the age of five years. Three hundred and forty children from University Teaching Hospitals – Children’s Hospital and Kamwala Health Centre in Lusaka were enrolled for the study. Information about immunisation against hepatitis B virus and medical history was collected. The children’s parents or guardians who were willing to be tested were also tested for hepatitis B virus infection. Three hundred and forty children and eleven guardians were sampled for this study One hundred and seventy-one (51.8 percent) were male children. The mean age was 13.2 months (SD = 16.07). There were 181(53.2 percent) children who were fully vaccinated against HBV while 35 (10.3 percent) were partially vaccinated and 96 (28.2 percent) were less than six weeks old hence had not yet received any hepatitis B vaccine. Immunisation status against hepatitis B of the remaining 28 (8.2 percent) was unknown. The prevalence of HBsAg positivity among children less than five years old was 1.5 percent. Three (60 percent) of those positive for hepatitis B were above three years. Factors such as sex, household income, hepatitis B vaccination status and history of blood transfusions were not associated with HBsAg positivity. However, the following factors were independently associated with HBV infection; maternal HIV infection, maternal HBV infection, child’s HIV infection and the child’s age. Age was an important factor independently associated with hepatitis B virus infection. For every increase of one month in child age, the odds for positive HBsAg increased by an average six percent (OR = 1.06, 95% CI = 1.01 – 1.11, P-value =0.03). The seroprevalence of HBsAg was 1.5 percent. There was no association between hepatitis B vaccination status and hepatitis B surface antigen positivity. There was an association between maternal HIV status and HBsAg positivity. There was also a non –significant association between maternal hepatitis B status and HBsAg positivity. Hepatitis B vaccine has had an impact on the prevalence of hepatitis B though this study did not show that association, however larger studies are needed to demonstrate this association. Key words: hepatitis B, vaccination era, Children’s Hospital-UTH, Kamwala Health Centre