Global HBV prevalence estimated at 3.9%
medwireNews: More than 290 million people, or 3.9% of the global population, are infected with hepatitis B virus (HBV), and while efforts to combat infection are improving, greater access to diagnosis and treatment is needed to meet global targets, report The Polaris Observatory Collaborators.
The team, led by Homie Razavi (Center for Disease Analysis Foundation, Lafayette, Colorado, USA), carried out a literature review to determine prevalence estimates for 128 countries, from which they developed dynamic HBV transmission and progression models for 120 countries, representing 93% of the global population and 90% of all estimated hepatitis B surface antigen (HBsAg)-positive infections.
Using these models, which accounted for the effect of HBV prophylaxis and treatment, they estimated that 291,992,000 people were positive for HBsAg in 2016. Of these, only around 29 million (10%) were diagnosed, and of 94 million individuals eligible for antiviral treatment in 2016, only 4.8 million (5%) actually received it.
In addition, approximately 1.8 million infections occurred in children aged 5 years, with a prevalence of 1.4% at this age.
Globally, 21 countries accounted for more than 80% of the total number of HBsAg-positive infections in 2016, with China, India, Nigeria, Indonesia, and the Philippines accounting for more than 57%.
Among children aged 5 years, just 16 countries accounted for more than 80% of estimated infections, with more than half occurring in Nigeria, India, Indonesia, and the Democratic Republic of the Congo.
The researchers estimated that 87% of infants had received the three-dose HBV vaccination in the first year of life, and 13% of infants born to HBsAg-positive mothers had received hepatitis B immunoglobulin along with the full vaccination regimen.
This “indicates that progress has been achieved in prevention of HBV; vaccination is succeeding and has had a substantial impact in many countries,” write Geoffrey Dusheiko, and Kosh Agarwal, both from King’s College Hospital in London, UK, in a comment that accompanies the study published in The Lancet Gastroenterology & Hepatology.
They add that “94 of the included countries are estimated to have met the interim 2020 target of 1% prevalence in children aged 5 years, and 46 are set to meet the 2030 target of 0.1% prevalence.”
However, Razavi and co-authors report that less than 1% of mothers with a high viral load had received antiviral therapy to reduce mother-to-child transmission.
But Dusheiko and Agarwal point out: “Timely birth-dose vaccination might offset the necessity for antiviral prophylaxis to reduce viral load in highly viraemic mothers.”
The current study estimated that 46% of infants had received timely birth-dose vaccination, and of the 16 countries with the greatest number of infected children aged 5 years, China was the only one with timely birth-dose coverage of 90% or higher.
This shows that “countries with a high HBV prevalence, such as China, can reduce the number of new infections through proactive national programmes,” say the researchers.
However, they conclude: “Although some regions are well on their way to meeting prophylaxis and prevalence targets, all regions must substantially scale-up access to diagnosis and treatment to meet the global targets.”
Dusheiko and Agarwal say that the modelled data could be used “to enable governments and health agencies to gauge and mount the effort necessary to control HBV.”
By Laura Cowen
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