Chronic and Occult Hepatitis B Virus Infection in Pregnant Women in Botswana

Abstract

The hepatitis B virus (HBV) is a global problem; however, the burden of HBV infection in pregnant women in Botswana is unknown. We sought to determine the prevalence of chronic and occult HBV infection in human immunodeficiency virus (HIV)-infected and -uninfected pregnant women in Botswana. Samples from 752 pregnant women were tested for hepatitis B surface antigen (HBsAg), and HBsAg-positive samples were tested for hepatitis B e antigen (HBeAg) and HBV DNA load. Samples that were HBsAg negative were screened for occult HBV infection by determining the HBV DNA load. HBV genotypes were determined based on a 415-base-pair fragment of the surface gene. Among the 752 women tested during pregnancy or early postpartum, 16 (2.1%) (95% confidence interval (CI): 2.0–2.2) were HBsAg-positive. The prevalence of chronic HBV infection was higher (3.1%) among HIV-infected (95% CI: 3.0–3.2) compared with HIV-uninfected women (1.1%) (95% CI: 1.07–1.1, p = 0.057). Among the 622 HBsAg-negative women, the prevalence of occult HBV infection was 6.6% (95% CI: 6.5–6.7). Three of thirteen HBsAg-positive participants were HBeAg-positive, and all were HIV-negative. Of the 11 maternal samples successfully genotyped, five (45.5%) were genotype D3, five (45.5%) were genotype A1, and one was genotype E (9%). Low and similar proportions of HIV-infected and -uninfected pregnant women in Botswana had occult or chronic HBV infection. We identified a subset of HIV-negative pregnant women who had high HBV DNA levels and were HBeAg-positive, and thus likely to transmit HBV to their infants.

Maternal Hepatitis B Virus Infection, Pregnancy, and Infant Health Outcomes in Botswana

“…Most HAART regimens in Botswana contain either tenofovir (TDF), lamivudine (3TC), or emtricitabine (FTC). These antiretrovirals have anti-HBV properties and could have resulted in the lower HBV prevalence in our cohort (5). A study by Anderson et al showed that there were 38% HB-sAg losses 24 months of post-Truvada-based cART initiation (17).…”

“…Occult HBV infection is defined as having negative HBsAg but positive HBV DNA. We previously reported a 6.6% prevalence of occult HBV in pregnant women in Botswana (5).…”

“…Maternal HBV-positive samples previously screened were used (5). One stored plasma sample from each participant taken at the delivery time was evaluated for HB-sAg using Murex HBsAg kit (Murex Biotech, Dartford, UK) and HBV DNA using COBAS ® AmpliPrep/COBAS ® Taqman ® HBV Test V.2.0 (Roche Diagnostics, Mannheim, Germany) with a lower limit of detection of 20 IU/mL.…”

“…One stored plasma sample from each participant taken at the delivery time was evaluated for HB-sAg using Murex HBsAg kit (Murex Biotech, Dartford, UK) and HBV DNA using COBAS ® AmpliPrep/COBAS ® Taqman ® HBV Test V.2.0 (Roche Diagnostics, Mannheim, Germany) with a lower limit of detection of 20 IU/mL. The testing was done at the Botswana Harvard HIV Reference Laboratory (BHHRL) following the methods described previously (5).…”

“…Botswana has been described by the World Health Organization (WHO) to have an intermediate prevalence of HBV (2). Between 5% and 10% of human immunodeficiency virus (HIV)-infected patients in Botswana have a positive hepatitis B surface antigen (HB-sAg) result (3,4) and the prevalence of HBsAg is 2.1% among pregnant women (HIV positive or negative) (5). Occult HBV infection is defined as having negative HBsAg but positive HBV DNA.…”