Viral and Bacterial Factors of Mother-to-Child Transmission of Hepatitis B Virus

Moussa Doumbia; Daouda Sevede; Viviane Kouakou; Cyprien Kouakou; Frederic Ahoke; Pascal Pineau; Mireille Dosso

Disclosures

J Viral Hepat. 2021;28(12):1683-1689. 

In This Article

Abstract and Introduction

Abstract

Hepatitis B virus (HBV) infection is the tenth leading cause of death worldwide. Mother-to-child transmission of HBV occurring mainly at delivery remains one of the most common routes of infection in developing countries. One of the main challenges concerning HBV in Africa is to implement a prevention policy aiming at interrupting the cycle of pseudo-vertical transmission of this infection. The aim of this study was to assess the implication of certain bacterial and viral factors in mother-to-child transmission of HBV. This prospective study was conducted on 165 pregnant women carriers of HBV surface antigen (HBsAg) and their 169 newborns who attended care at the Gynecology Department of the University Hospital of Cocody. Serological, molecular, and bacteriological analyses were performed on blood samples and vaginal secretions. Mean viral load (VL) was 4.5 ± 1.3 log10 IU/ml, while mean HBsAg titres were 3.5 ± 0.9 log10 IU/ml. HBV DNA was found in vaginal secretions in 13.3% of mothers and in the blood of 10.3% of the newborns. Six bacterial species were identified in the vaginal discharge of pregnant women during labour before delivery. Staphylococcus aureus and Enterococcus faecalis were the most frequent species found in 23.0% and 13.9% of cases. Mothers positive for vaginal HBV DNA displayed higher plasma HBV DNA loads than negative mothers (6.2 ± 1.6 log10 IU/ml vs. 4.3 ± 1.0 log10 IU/ml, p < .0001). In conclusion, our study showed that presence of HBV DNA in vaginal secretions and the presence of S. aureus could play a role in mother-to-child transmission of HBV. HBV DNA detection in vaginal discharge represents a promising biomarker to identify newborns at risk of perinatal persistent infection.

Introduction

Hepatitis B virus (HBV) infection occupies a prominent place in the global burden of disease as around 250 million people are living with viral hepatitis B. Each year, 900,000 deaths are caused by hepatitis B virus infection. Only 10% of people living with hepatitis B know their status and 42% of children globally have access to a birth dose of anti-hepatitis B vaccine.[1] This infection is the leading risk factor for liver cancer, the third deadliest malignancy in the world.[2] The prevalence of chronic infection was recently established at 5.4% in Morocco, compared to 1.0% for HIV and 3.0% for viral hepatitis C.[3]

Sub-Saharan Africa remains one of the areas the most affected by HBV.[4] In Côte d'Ivoire in particular, the prevalence of chronic infection is high and ranges between 8% and 10%.[5,6] One of the suspected most common HBV transmission routes, essentially present in low and middle-income countries, remains mother-to-child transmission (MTCT).[7] However, its importance is not precisely defined in many countries located in sub-Saharan Africa. In Côte d'Ivoire, for example, MTCT rate was estimated at 32.8% two decades ago.[8] MTCT is not truly vertical because in utero transmission is rare, but it is rather perinatal (or pseudo-vertical).[9] It occurs at the time of delivery (per partum), secondarily to mother-to-child micro-transfusions during contractions and by contact with infected vaginal secretions. This route of transmission is thought to be responsible for more than a third of chronic viral hepatitis because newborns are immune tolerant and, once infected, develop a persistent form of HBV infection in 80–90% of cases.[10,11] Children infected with HBV at birth represent an important viral reservoir that maintains hyperendemicity in the affected areas.[12]

Available data from Côte d'Ivoire only cover certain aspects of the molecular epidemiology of HBV such as the most common viral genotypes[13–16] as well as its prevalence in certain populations such as blood donors and HIV positive people.[17]

The main contemporary challenge is to implement a preventive policy aiming to interrupt the cycle of pseudo-vertical transmission of this infection. However, such prevention is difficult to achieve either due to the lack of financial resources or to the lack of knowledge regarding certain biological factors such as the role of the vaginal microbiota in the vertical transmission of hepatitis B. Very few studies have proven the involvement of the vaginal flora in mother-to-child transmission of HBV.[18]

This study aimed to evaluate the role of viral and bacterial factors in MTCT of hepatitis B in Côte d'Ivoire.

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