'Step-change in strategy' needed to eliminate HBV as a global health threat

Michael Carter
Published:
11 October 2016

Hepatitis B virus (HBV) could be eliminated as a global health threat with a scale-up of vaccination coverage, enhanced efforts to prevent vertical (mother-to-child) transmission and expansion of testing and treatment, according to a modelling study published in The Lancet Infectious Diseases. With these interventions, incidence of new chronic infections could be reduced by 90% and mortality rates by two-thirds between 2015 and 2030. HBV-related mortality could be eliminated in Western Europe as soon as 2017 but it would take until 2090 to achieve this goal in sub-Saharan Africa. The total cost of the strategy would be approximately $88 billion, but this would fall if a cure were developed.

“Maintenance of a business as usual approach will not end the epidemic and will lead to 17 million avoidable deaths over the next 15 years,” comment the authors. “A comprehensive and ambitious package of interventions that tackle prevention and treatment could lead to a 90% reduction in incidence of new chronic infections and a 65% reduction in worldwide mortality by 2030.”

A highly effective vaccine against HBV exists and antiviral treatment for chronic infection is also available. Coverage of these interventions is low in some world regions, and HBV continues to cause approximately 687,000 deaths each year, even though the World Health Organization (WHO) aspires to the elimination of HBV as a global health threat. 

An international team of investigators therefore developed a model to evaluate the impact of current public health interventions against HBV, propose targets for reductions in incidence and mortality, and identify key interventions required to eliminate the global health threat posed by HBV.

The model incorporated data on the natural history of the infection, prevalence, mortality, vaccine coverage, treatment and demographics. The investigators first estimated the impact of current interventions and examined the effect of their scale up and the introduction of population-wide screening and treatment.

The model estimated 850,000 HBV deaths and a global prevalence of 290 million individuals in 2010, consistent with other epidemiological data. In 2010, 30% of HBV-related deaths, 70% of new chronic infections and 40% of people living with the infection were in the five world regions with the most low and middle-income countries.

With current interventions, the model predicted 4.3 million new chronic infections, 1 million HBV-related deaths and 270 million people living with HBV by 2020.

Between 2020 and 2050, the number of new infections would drop by 70% as a result of sustained vaccination coverage and there would also be a 40% reduction in the number of people living with HBV, mainly due to declining incidence and deaths in an ageing population. The number of HBV-related deaths would increase to 1.14 million per year by 2034 and then decline to 1.06 million per year by 2050.

Vaccination scale-up has already had a substantial impact on the epidemic. Without any infant vaccination or birth-dose vaccination, there would be 25 million new cases by 2020. Therefore, vaccination has already reduced new cases by 83% and cumulatively prevented 310 million infections between 2010 and 2020.

However, existing interventions have not substantially reduced the number of individuals living with chronic HBV (30% reduction by 2020 vs no interventions) or HBV-related deaths (4% reduction by 2020 vs no interventions). This lack of progress was attributed to lack of treatment scale-up.

Without further expansion of interventions, the number of people living with HBV will remain at the same high levels for up to 50 years. Worldwide, there will be 63 million new chronic infections and 17 million HBV-related deaths between 2015 and 2030.

Scaling up infant vaccination levels to 90% globally will prevent 4.3 million new infections between 2015 and 2030 compared to the status quo. Addition of birth-dose vaccination, and increasing pre-delivery antiviral treatment for mothers with chronic HBV infection to 80% coverage will avert a further 19.3 million new infections.

Test-and-treat interventions with 80% coverage will reduce deaths by 65%, preventing 7.3 million deaths between 2015 and 2030.

Half of world regions will achieve elimination of new chronic infections by 2060 with scale-up of these interventions. Western Europe could eliminate HBV-related deaths by 2017 but sub-Saharan Africa and Asia would not attain this goal until closer to 2090.

The average global cost of these scaled up interventions will be $5.5 billion annually between 2015 and 2030. Most of the expenditure will be on screening (39%) and treatment (59%). Costs will peak at $7.5 billion annually but will fall rapidly to $4.7 billion a year in 2030, with further reductions thereafter. The total net cost will be $88.7 billion by 2030 falling to $84 billion should a cure for HBV be developed.

“The current global approach to tackle HBV – a reliance on infant vaccination – has brought enormous health gains, but a step-change in strategy will be needed to bring a target of HBV elimination within reach,” conclude the investigators. “This change must see a large increase in the proportion of births that benefit from a package of interventions and in the proportion of people with chronic HBV carriage who are diagnosed and treated when eligible, as well as maintenance and expansion of infant vaccination programmes.”

Reference

Nayagam S et al. Requirements for global elimination of hepatitis B: a modelling study. The Lancet Infect Dis, http://dx.doi.org/10.1016/s1473-3099(16)30204-3 (2016).