The clinical implications of hepatitis B virus genotypes and HBeAg in pediatrics

Abstract

SummaryAlthough a successful vaccine against HBV has been implemented in 184 countries, eradication of hepatitis B virus (HBV) is still not on the horizon. There are over 240 million chronic carriers of HBV globally. The risk of developing chronic hepatitis ranges from >90% in newborns of hepatitis Be antigen (HBeAg)‐positive mothers, 25%–35% in children under 5 years of age and <5% in adults. HBeAg, a non‐particulate viral protein, is a marker of HBV replication. This is the only HBV antigen to cross the placenta, leading to specific unresponsiveness of helper T cells to the capsid protein and HBeAg in newborns. HBeAg is tolerated in utero and acts as a tolerogen after birth. Perinatal transmission is frequent when mothers are HBeAg‐positive, whereas it occurs less frequently when mothers are HBeAg‐negative. Sequence heterogeneity is a feature of HBV. Based on an intergroup divergence >7.5% across the complete genome, HBV is classified phylogenetically into at least nine genotypes. With between ~4% and 8% intergroup nucleotide divergence, genotypes A–D, F, H and I are classified further into subgenotypes. HBV genotypes/subgenotypes may have distinct geographical distribution and can develop different mutations in the regions of the HBV genome that code for HBeAg. These differences can be related to the role of HBV genotypes to the natural history of infection and mode of transmission. Thus genotypes/subgenotypes of HBV can be responsible for the different natural history of infection and modes of transmission in children, found in various regions of the world, where different genotypes/subgenotypes prevail. Copyright © 2016 John Wiley & Sons, Ltd.

Early experiences from one of the first treatment programs for chronic hepatitis B in sub-Saharan Africa

“…This is in line with previous studies indicating that African CHB patients have a lower rate of HBeAg positivity compared to those in the Far East [21]. This phenomenon is explained, at least partly, by geographical variations in HBV genotypes and mode of transmission [22]. Indeed, over the past few decades, HBeAg negative CHB has become the commonest type of HBV infection in many countries of the world.…”

Early childhood transmission of hepatitis B prior to the first hepatitis B vaccine dose is rare among babies born to HIV-infected and non-HIV infected mothers in Gulu, Uganda

“…Indeed, a recent study revealed that HBV genotypes A and D which are more efficiently transmitted by horizontal means [24] are the most predominant in Uganda [25]. Data indicate that individuals with HBV sub-genotype A1 and genotype D usually seroconvert to anti-HBe (HBeAg negative) status before their gestation age [26,27]. Thus, they are less likely to have significant ongoing HBV replication when they start conceiving.…”

“…Unlike Southeast Asia, where vertical transmission is the predominant route of disease transmission, our findings support the hypothesis that majority of HBV infections in SSA are acquired through horizontal means. Horizontal transmission of HBV can be prevented through vaccination even during the 6 week first dose inoculation [26]. It is not clear why there is a high HBV prevalence in northern Uganda but we hypothesize that it is most probably a result of using unsterile equipment for cultural practices such as scarification.…”

Retrospective Analysis of Viral Hepatitis B Incidence in Russia from 2013 to 2017 in the Context of Preventive Vaccination

“…На основе различий между нуклеотидными последовательностями ВГВ подразделяют на 10 генотипов, обозначенных латинскими буквами от А до J. Генетическая вариабельность составляет 8 %. Клиническая картина заболевания зависит от генотипических особенностей ВГВ [2,3]. В Российской Федерации развитие эпидемического процесса гепатита В обусловлено циркуляцией вируса гепатита В генотипов D и А (92 и 8 % лиц соответственно) 3 .…”

“…Клиническая картина заболевания зависит от генотипических особенностей ВГВ [2,3]. В Российской Федерации развитие эпидемического процесса гепатита В обусловлено циркуляцией вируса гепатита В генотипов D и А (92 и 8 % лиц соответственно) 3 .…”