Hepatitis B virus (HBV): serological markers of infection and immunity in a cohort of South African children

Children age 6-60 months were recruited as part of the Co-infection in South-African Children (COSAC) study, in Kimberley, South Africa. HIV-negative participants (n=174) were recruited through the Kimberley Respiratory Cohort (KReC). These children were admitted to hospital with a clinical diagnosis of respiratory tract infection between July 2014 and August 2016. HIV-positive children (n=136) were recruited primarily from HIV outpatient clinics, (recruited between September 2009 and July 2016). Children had research blood samples taken at the same time as routine clinical blood tests. We tested all samples for markers of hepatitis B virus (HBV) infection and immunity. HBsAg testing was carried out in Kimberley Hospital, South Africa using the Magnetic parcel chemiluminometric immunoassay (MPCI; Advia Centaur platform). Confirmatory HBsAg testing, together with anti-HBs and anti-HBc testing, was carried out by the microbiology department at Oxford University Hospitals (OUH) NHS Foundation Trust, Oxford, UK (Architect i2000). Ethics approval for this study was obtained from the Ethics Committee of the Faculty of Health Science, University of the Free State, Bloemfontein, South Africa (HIV Study Ref: ETOVS Nr 08/09 and COSAC Study Ref: ECUFS NR 80/2014). Written consent for enrollment into the study was obtained from the child’s parent or guardian.