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Global HDV rates highest among HBV coinfected with risky behaviors

The global number of individuals infected with hepatitis D and positive for hepatitis B surface antigen was twofold higher than previous estimates among those without high-risk behaviors and even higher among people who inject drugs or partake in risky sexual behavior, according to a recently published systematic review.

“Our study showed that the global burden of HDV infection is not abated and has been underestimated,” Hai-Yan Chen, MD, from the First Affiliated Hospital of Nanjing Medical

University in China, and colleagues wrote. “Moreover, the testing rates for HDV antibodies in the HBsAg-positive individuals are inappropriately low, which suggests a lack of awareness regarding the availability of a test for HDV in the Europe.”

To better understand the global burden of HDV, Chen and colleagues performed a systematic review and meta-analysis of 182 international studies published between Jan. 1, 1977, and Dec. 31, 2016. The studies comprised a total of 40,127,988 individuals, representing approximately 0.54% of the global population.

Results of the review showed that HDV prevalence was 0.98% (95% CI, 0.61-1.42) in the general population and 14.57% (95% CI, 12.93-16.27) among individuals positive for HBsAg.

Among those positive for HBsAg, HDV seroprevalence was 10.58% (95% CI, 9.14-12.11) among individuals without a history of intravenous drug use or risky sexual behavior. HDV seroprevalence was higher among people with high-risk sexual behavior (17.01%; 95% CI, 10.69-24.34) and people who inject drugs (37.57%; 95% CI, 29.3-46.2) and correlated significantly with both risk factors.

As the HBV vaccine was recommended to be included in the expanded gram of immunization for all countries in 1997, the researchers also reviewed HDV prevalence according to the year range of 1977 to 1996 (group A) and from 1997 to 2016 (group B).

“As expected, the prevalence of HDV infection in group B was lower than that in group A,” the researchers wrote. “There was a definite association between the HBV vaccine coverage rate and the HDV prevalence.”

HDV seroprevalence also varied based on a region’s sociodemographic index (SDI) and development. Prevalence rates were lowest in high-middle SDI countries (0.07%; 95% CI, 0.0-0.53), followed by high SDI countries (0.42%; 95% CI, 0.08-0.93) and middle SDI countries (1.08%; 95% CI, 0.5-1.85), and lowest in low-middle SDI countries (1.85%; 95% CI, 0.8-3.26) and low SDI countries (3.41%; 95% CI, 0.85-7.36).

“The results of this study stress on the need for the international guidelines of HDV screening in HBsAg-positive individuals, especially in the [intravenous drug user] and [high-risk sexual behavior] population,” Chen and colleagues wrote. “HBV vaccine has a defensive effect on the infection by HDV. Considering the lower HBV immunization coverage in lower SDI countries, the implementation of HBV vaccination program should also be pushed further in poor-resourced countries.” – by Talitha Bennett

Disclosure: The authors report no relevant financial disclosures.