What does the scale-up of long-acting HIV pre-exposure prophylaxis mean for the global hepatitis B epidemic?

INTRODUCTION: The HIV and hepatitis B virus (HBV) epidemics are interconnected with shared routes of transmission and specific antiviral drugs that are effective against both viruses. Nearly, 300 million people around the world live with chronic HBV, many of whom are from priority populations who could benefit from HIV prevention services. Oral pre-exposure prophylaxis (PrEP) for HIV has implications in the prevention and treatment of HBV infection, but many people at increased risk of HIV acquisition may instead prefer long-acting formulations of PrEP, which are currently not active against HBV. DISCUSSION: People at increased risk for HIV acquisition may also be at risk for or already be living with HBV infection. Oral PrEP with tenofovir is effective in preventing both HIV and HBV, and tenofovir is also the recommended treatment for chronic HBV infection. Although implementation of oral PrEP has been challenging in sub-Saharan Africa, investments in its scale-up could secondarily reduce the clinical impact of HBV. Long-acting PrEP, including injectable medicines and implantable rings, may overcome some of the implementation challenges associated with oral PrEP, such as daily pill burden, adherence challenges and stigma; however, current formulations of long-acting PrEP do not have activity against HBV replication. Ideally, PrEP programmes would offer both oral and long-acting formulations with HBV screening to optimize HIV prevention services and HBV prevention and care, when appropriate. People who are not immune to HBV would benefit from being vaccinated against HBV before initiating long-acting PrEP. People who remain non-immune to HBV despite vaccination may benefit from being offered oral, tenofovir-based PrEP given its potential for HBV PrEP. People using PrEP and living with HBV who are not linked to dedicated HBV care would also benefit from laboratory monitoring at PrEP sites to ensure safety when using and after stopping tenofovir. PrEP programmes are ideal venues to offer HBV screening, HBV vaccination for people who are non-immune and treatment with tenofovir-based PrEP for people with indications for HBV therapy. CONCLUSIONS: Long-acting PrEP holds promise for reducing HIV incidence, but its implications for the HBV epidemic, particularly in sub-Saharan Africa, should not be overlooked.

Virological, serological and clinical outcomes in chronic hepatitis B virus infection: development and validation of the HEPA-B simulation model.

OBJECTIVES: Detailed simulation models are needed to assess strategies for prevention and treatment of hepatitis B virus (HBV) infection, the world's leading cause of liver disease. We sought to develop and validate a simulation model of chronic HBV that incorporates virological, serological and clinical outcomes. METHODS: We developed a novel Monte Carlo simulation model (the HEPA-B Model) detailing the natural history of chronic HBV. We parameterised the model with epidemiological data from the Western Pacific and sub-Saharan Africa. We simulated the evolution of HBV DNA, 'e' antigen (HBeAg) and surface antigen (HBsAg). We projected incidence of HBeAg loss, HBsAg loss, cirrhosis, hepatocellular carcinoma (HCC) and death over 10-year and lifetime horizons. We stratified outcomes by five HBV DNA categories at the time of HBeAg loss, ranging from HBV DNA<300 copies/mL to >106 copies/mL. We tested goodness of fit using intraclass coefficients (ICC). RESULTS: Model-projected incidence of HBeAg loss was 5.18% per year over lifetime (ICC, 0.969 (95% CI: 0.728 to 0.990)). For people in HBeAg-negative phases of infection, model-projected HBsAg loss ranged from 0.78% to 3.34% per year depending on HBV DNA level (ICC, 0.889 (95% CI: 0.542 to 0.959)). Model-projected incidence of cirrhosis was 0.29-2.09% per year (ICC, 0.965 (95% CI: 0.942 to 0.979)) and HCC incidence was 0.06-1.65% per year (ICC, 0.977 (95% CI: 0.962 to 0.986)). Over a lifetime simulation of HBV disease, mortality rates were higher for people with older age, higher HBV DNA level and liver-related complications, consistent with observational studies. CONCLUSIONS: We simulated HBV DNA-stratified clinical outcomes with the novel HEPA-B Model and validated them to observational data. This model can be used to examine strategies of HBV prevention and management.

Risks and benefits of oral HIV pre-exposure prophylaxis for people with chronic hepatitis B.

Individuals with chronic hepatitis B virus (HBV) infection who are at substantial risk of HIV acquisition benefit from pre-exposure prophylaxis (PrEP) with tenofovir-based antiviral therapy. Considering that tenofovir potently inhibits HBV, providing PrEP to individuals with HBV effectively results in treatment of their HBV infection. However, some clinicians might be hesitant to initiate PrEP in people with chronic HBV due to unknown risks of HBV reactivation, hepatitis, and acute liver failure during periods of antiviral cessation. Unfortunately, these knowledge gaps affect scale up of PrEP among people with chronic HBV. Emerging data regarding the risks and benefits of antiviral cessation in people with chronic HBV suggest that PrEP can be safely initiated despite the risks of non-adherence or discontinuation. People with chronic HBV who stop PrEP should be closely monitored for HBV reactivation and hepatitis flares after antiviral cessation.

Clearance of Hepatitis B e Antigen in Untreated Chronic Hepatitis B Virus Infection: A Systematic Review and Meta-analysis.

BACKGROUND: In people with hepatitis B virus (HBV) infection, persistence of hepatitis B e antigen (HBeAg) is associated with clinical progression and need for treatment. HBeAg loss represents partial immune control and is a critical event in the natural history of chronic HBV. METHODS: We conducted a systematic review and meta-analysis of cohort studies that report HBeAg loss among people with untreated chronic HBV. We evaluated HBeAg loss using a random-effects model and conducted subanalysis on region. RESULTS: We screened 10 560 publications, performed 196 full-text analyses, and included 26 studies for meta-analysis. The pooled rate of HBeAg loss was 6.46/100 person-years (PYs) (95% confidence interval, 5.17-8.08). Meta-regression showed that older age of participants and studies in Europe were associated with higher rate of HBeAg loss. Rates per 100 PYs were 7.43 (95% confidence interval, 6.30-8.75; 1 study) in Africa, 3.24 (2.61--4.02; 1 study) in the Eastern Mediterranean, 13.67 (11.21-16.66; 4 studies) in Europe, 7.34 (4.61--11.70; 5 studies) in North America, and 5.53 (4.05--7.55; 15 studies) in the Western Pacific. CONCLUSIONS: Spontaneous HBeAg loss occurs at a rate of 6.46/100 PYs. Variations by region and age group may reflect epidemiological, immunological, or HBV genotype-related differences.

Hepatitis B virus activity in untreated hepatitis B e antigen-negative human immunodeficiency virus-hepatitis B virus co-infected patients from sub-Saharan Africa.

BACKGROUND: In human immunodeficiency virus (HIV) and hepatitis B virus (HBV) co-infected patients from sub-Saharan Africa with hepatitis B e antigen (HBeAg)-negative status, data are limited on the evolution of HBV activity when antiretroviral treatment (ART) is absent. METHODS: A total of 43 HBeAg-negative co-infected patients not indicated for ART (per concomitant World Health Organization recommendations) were followed during participation in a randomized controlled trial in Côte d'Ivoire. Chronic HBeAg-negative phases were classified at yearly visits and defined as 'infection' (HBV DNA ≤10 000 copies/mL and normal alanine aminotransferase [ALT]) or 'hepatitis' (HBV DNA >10 000 copies/mL and/or above normal ALT). Dispersion in HBV DNA and ALT levels during follow-up was assessed using interquartile range (IQR) regression. RESULTS: During a median 25 months (IQR 19-31), 17 (40%) patients consistently had 'infection', 5 (12%) consistently had 'hepatitis' and 21 (48%) fluctuated between phases. Wider dispersion in HBV DNA over time was associated with higher baseline HIV RNA (p=0.02) and higher baseline HBV DNA levels (p=0.008), while wider dispersion in ALT was associated with higher baseline HIV RNA (p<0.001), higher baseline ALT levels (p=0.02) and baseline hepatitis surface antigen >4.0 log10 IU/mL (p=0.02). CONCLUSIONS: HBV activity is common with HBeAg-negative status, whose variation is partly linked to HIV replication. Fluctuations in disease phase make it difficult to assess the risk of morbidity and mortality after ART initiation.