1 INTRODUCTION
Blood components are used by health services around the world for the
treatment of numerous clinical conditions. Therefore, the safety of
blood products remains a major concern for blood collection centers,
mainly due to transfusion-transmitted viruses (TTVs), such as hepatitis
B virus (HBV). HBV is prevalent in blood donors worldwide and
constitutes a serious global public health problem, especially in low-
and middle-income countries (LMICs). Globally, more than 2 billion
people, equivalent to about a third of the world population, have
already been infected with HBV, of which 350 million people have
developed chronic hepatitis infection. Geographic regions are classified
as highly endemic (8%), intermediate (2 to 7%), and low endemic
(<2%). The African continent is an area of high HBV
endemicity compared to the other geographical regions.
Due to improvements in the criteria for selecting eligible donors for
blood donation, the risk of transmitting viruses such as HBV has
decreased significantly in recent years, even so, surveillance to
estimate the risk of HBV transfusion in blood donors remains essential
to monitor the safety of the blood supply as well as the impact of new
screening tests, especially in areas of high HBV endemicity. HBV surface
antigen (HBsAg) along with HCV, HIV, and syphilis screening remains the
keys biological marker used for screening blood donors for sexual
transmission infections. However, studies have shown that HBV mutations
associated with structural changes in HBsAg and circulating immune
complexes could negatively affect the performance of HBsAg detection,
suggesting the inclusion of other biomarkers along with HBsAg although
the cost and equipment requirements of these assays might limit their
use in LMICs.
The biological markers aspartate transaminase (AST) and alanine
aminotransferase (ALT) as well as the ratio of the AST/ALT have always
been used in clinical practice to reflect liver injury and have been
associated with some human diseases, including chronic diseases and
mortality. Previous studies showed that serum determination of AST and
ALT enzymes as well as their proportion is a clinically valuable
procedure for differentiating viral hepatitis from other icteric
diseases along with markers of infection, antibodies, and antigens.
Despite the high endemicity of HBV in Angola, few studies have been
carried out, for the screening of HBV infection in the asymptomatic or
healthy population. To the best of our knowledge, there is no study
published assessing the determinants of HBV infections along with the
clinical profile of liver function in HBV-infected individuals in
Angola. In this study, we combine sociodemographic and clinical features
related to HBV infection as well as the clinical progression to chronic
liver disease among HBV-positive blood donors rejected for blood
donation in Luanda, the capital city of Angola, in order to (i) avoid
the TTVs, (ii) improve the safe blood products, and (iii) control the
spread of HBV infection in Angola. Furthermore, this study presents the
epidemiological picture of HBV and could serve to reflect the status of
HBV prevention and vaccination programs in Angola.