News Release

The Lancet Gastroenterology & Hepatology: Almost 300 million people have hepatitis B virus worldwide, but just 1 in 20 of those eligible receive treatment

Peer-Reviewed Publication

The Lancet

  • Globally, 90% of people with hepatitis B (HBV) are undiagnosed; two-thirds of those with HBV in the USA, and 4 in 5 in the UK, are unaware of their infection
  • Three-quarters of eligible patients in the UK not receiving treatment
  • Progress in child vaccination, but 1.8 million 5-year-olds infected globally in 2016
  • Half of babies worldwide still do not receive life-saving vaccine at birth
  • Some progress in prevention--46 countries have already met the 2030 target of ?0.1% prevalence among 5-year-olds

Around 300 million people in 2016 were living with hepatitis B virus (HBV) worldwide, yet just 1 in 20 (5%) eligible patients are getting treatment [1]. Moreover, less than 1% of HBV-infected expectant mothers, who are at high risk of passing the virus on to their children and are the main source of the ongoing epidemic, are receiving the appropriate treatment.

The research, published in The Lancet Gastroenterology & Hepatology, provides the most detailed analysis of national, regional, and global prevalence of HBV infection around the world to date (for individual country data see table 1).

The authors from the Polaris Observatory (Center for Disease Analysis Foundation, Lafayette, USA) warn that the WHO targets toward elimination of HBV are unlikely to be achieved by 2030 without a rapid scale-up in access to screening and treatment in most countries [2].

Previous estimates of the HBV disease burden have not considered the impact of prevention strategies or changing prevalence over time, and this is also the first analysis to exclude studies done in blood donors, which typically report a low prevalence, and other non-representative populations.

If left untreated, HBV can cause a host of serious, long-term health problems including liver disease, and liver cancer. An estimated 600,000 people die every year from hepatitis-B-related liver disease [3]. The virus is highly contagious and is mainly transmitted from infected mothers to their babies, or between children. Although there is no cure, antiviral drugs and prophylaxis to minimise mother-to-child transmission make elimination of HBV feasible. A highly effective vaccine against HBV became available in 1981, and since 1992, WHO has recommended that all newborns receive their first dose within 24 hours of birth. Babies born to HBV-infected mothers should also be given protective antibodies known as hepatitis B immunoglobulin (HBIG).

Five countries account for more than half of all HBV infections

By analysing data from 435 studies and 620 national experts, the researchers calculated that the historical global prevalence of HBV infection was 4.9%, or around 364 million people. They then generated updated estimates of country-level and global prevalence and management using a dynamic transmission and progression model, which incorporated data on epidemiology, vaccination coverage, treatment, and diagnosis. The new estimates reveal that 292 million individuals were living with HBV in 2016, equivalent to a prevalence of 3.9%--suggesting that progress has been made in controlling infection worldwide.

The findings show that the virus is most common in east Asia and sub-Saharan Africa, where prevalence is as high as 12.1% (Central African Republic) compared to 0.7% in the UK (table 1). In 2016, 21 countries accounted for more than 80% of all HBV infections, with China, India, Nigeria, Indonesia, and the Philippines accounting for over 57% of all infections (figure 4A).

Undiagnosed and untreated HBV--a serious global health threat

Although a diagnostic test for HBV infection has been available since the early 1970s, only 1 in 10 of those infected worldwide (around 29 million) had been diagnosed by 2016. The estimates indicate that diagnosis is not just a problem in low- and middle-income countries--two-thirds of those with HBV in the USA, and 4 in 5 in the UK, are unaware of their infection (table 1).

Furthermore, the authors calculate that just 5% (4.8 million of 96 million) of those suitable for treatment received antiviral therapy in 2016 (figure 2, table 2). In Western Europe, the proportion of eligible patients receiving treatment ranged from 3% (480) in Belgium, and 5% in Ireland (60), Norway (220), and Portugal (1800), to 95% (2700) in Finland. In the UK, only a quarter (27,900) of those eligible had received treatment in 2016 (table 1).

Worryingly, say the authors, less than 1% of HBV-infected expectant mothers with high viral load--the highest risk group for passing the infection on to their children--received antiviral prophylaxis to prevent mother-to-child infection in 2016. This leaves open the crucial role of mother-to-child transmission as a reservoir for future cases in many high-burden countries.

Progress in child vaccination, but half of babies not receiving life-saving vaccine at birth

Despite being preventable, 1.8 million 5-year-olds (1.4%) had HBV in 2016. But there are signs of progress. Globally, in 2016, 87% of infants had received the three vaccine doses necessary to prevent the disease. What's more, 94 of the 120 modelled countries have already met the interim 2020 target of 1% prevalence among 5-year-olds, and 46 have already met the 2030 target of 0.1% prevalence.

However, less than half of babies are getting their first vaccination within 24 hours of birth, and just 1 in 10 babies born to HBV-infected mothers are receiving HBIG along with the full vaccination schedule (figure 3). In 2017, the UK and Norway became two of the last countries in Europe to offer the vaccine to newborns.

"Most mother-to-child transmission occurs within days of birth, so the birth dose is vital", explains primary investigator Dr Homie Razavi from the Center for Disease Analysis Foundation, Lafayette, USA. "All children need to receive this life-saving vaccine at birth, not just half of them." [4]

Of the 16 countries that account for more than 80% of infections among 5-year-olds (figure 4B), only China has scaled-up timely birth-dose coverage to 90%. What's more, 10 of these countries have yet to introduce universal timely birth dose vaccination. For example, in Pakistan birth dose and HBIG are only available in the private sector. The authors note some limitations, including that the quality of the available studies varied across countries, with a lack of high-quality data available from African nations (figure 1A). They also note that the model does not explicitly take into account certain populations that might have a higher prevalence, including immigrants and sex workers, nor does it account for the substantial numbers of HIV-HBV or HBV and HDV coinfected individuals, in whom disease tends to progress more rapidly. This could result in prevalence being under or overestimated.

Lessons learnt from HIV/AIDS could help fight against HBV

"We have all the tools necessary to eliminate HBV," says Dr Razavi. "Our estimates highlight an enormous opportunity for effective screening, diagnosis, and treatment to substantially reduce the numbers of new infections in all countries by 2030. But we must accelerate efforts across the board. We hope this work will be the catalyst to support national strategies to eliminate the virus by 2030--which 194 countries have pledged to do."[4]

Writing in a linked Comment, Professor Geoffrey Dusheiko and Dr Kosh Agarwal from UCL Medical School and Kings College Hospital, London, UK discuss the lessons derived from this model of the global burden of hepatitis B. "Successive governments in high-prevalence regions have accepted the doctrine of vaccination, but have overlooked the larger picture of screening, diagnosis, and treatment to prevent progression... The incidence of new chronic HBV infections will continue to increase unless appropriate prevention at birth is applied, and deaths will increase in unvaccinated adults unless large increases in screening and linkage to care are implemented. However, large-scale structural changes might not be required if existing HIV services are utilised. The Article details the inadequate focus and expenditure on HBV treatment (despite the low annual costs of generic nucleoside analogues for those required to pay for health care out of pocket). There is a need to raise awareness of HBV to the same level as that of HIV and a pressing prerequisite for inexpensive, innovative, point-of-care nucleic acid testing for HBV DNA, paired with hepatitis C virus RNA and HIV RNA assays."

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NOTES TO EDITORS This study was funded by John C Martin Foundation

[1] An individual with HBV infection is eligible for treatment if they have a high viral load ( >=20,000 IU/mL), or have progressed to at least cirrhosis.

[2] World Health Assembly elimination targets include 90% coverage of HBV vaccination and vaccination at birth, and a reduction of HBV prevalence in 5-year-olds to 0.1%, and improved treatment rates to 80% by 2030.

[3] https://www.cdc.gov/hepatitis/hbv/pdfs/hepbatrisk.pdf

[4] Quotes direct from author and cannot be found in text of Article.

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