Hepatitis B Prevalence High Among US Immigrants

Rates of hepatitis B virus (HBV) screening and vaccine-induced immunity are lacking in regions of the world where the virus remains endemic, according to new cohort data analyses.

In research presented at The Liver Meeting 2023 from the American Association for the Study of Liver Disease (AASLD) in Boston this month, a team of US-based investigators reported that the prevalence of HVB remains ≥5.0% in the population of 8 countries. Among those countries, just 1 has screened a majority of eligible individuals for HBsAg, and 2 have immunized ≥70% of the eligible population.

Led by Matt Sumethasorn, MD, a second-year resident with the USC / Los Angeles General Medical Center Internal Medicine Residency Program, investigators sought to provide a current epidemiological estimate of country- and region-specific HBV screening, prevalence and immunity rates through a large US cohort enriched for foreign-born individuals. They noted the current recommendation from the Centers for Disease Control and Prevention (CDC) that all adults ≥18 years old are screened ≥1 time for HBV, regardless of their disclosure of risk.

“Chronic HBV continues to be a global health problem with high morbidity and mortality despite readily available and effective therapeutics due to inadequate awareness of infection,” they wrote. “HBV seroprevalence is substantially higher in foreign-born persons than the general US population.”

Sumethasorn and colleagues conducted a retrospective analysis of adults ≥18 years old with ≥2 outpatient primary care visits at a large, highly foreign individual-representative, Los Angeles-based healthcare system from 2017 – 2021. The team estimated country and region-specific HBV screening rates as the proportion tested for HBsAg from all eligible individuals.

Investigators estimated age-adjusted HBV prevalence as the proportion of persons with positive HBsAg among those screened, while those who tested negative were examined for the frequency of HBsAb testing. Immunity rates for HBV were defined as HBsAb titers of ≥12 U/L among those who tested negative.

To identify country- and region-specific prevalence, the team used the 6 World Health Organization (WHO) regions and identified countries with ≥100 screened persons for the country analyses.

The final analysis included >200,000 persons with inclusion criteria across 174 unique countries of birth; a majority (86.2%) were from the Region of the Americas. Median age was 55 years old; 41.2% were male, and 38% were born in the US.

Investigators observed an age-adjusted HBV prevalence of 0.4% (95% CI, 0.3 – 0.5) among US-born individuals—versus a 1.2% prevalence (95% CI, 1.1 – 1.3) among foreign-born individuals. All 6 regions reported HBV screening rates of <45%, and Region of the Americas and European Region reported <30% immunity rates.

Only Afghanistan and Cambodia were the observed countries to provide a >50% screening rate. Immunity rates varied significantly, from 9.1% (95% CI, 0.2 – 42.3) in Chile to 77.8% (95% CI, 57.7 – 91.4) in Myanmar. Immunity rates were 36.0% (95% CI, 35.3 – 36.7) among US-born individuals, versus 26.7% (95% CI, 26.2 – 27.2) among foreign-born individuals.

Nearly all countries with ≥5% estimated prevalence of HBV were located in Asia, and included Vietnam (12.8%); China/Taiwan/Hong Kong (10.5%); Cambodia (10.2%); North Korea (8.2%); Thailand (7.2%); Myanmar (7.2%); Nigeria (5.5%); and Ethiopia (5.1%).

Sumethasorn and colleagues concluded that high HBV prevalence is continually observed among US immigrants from endemic countries.

“Low HBV screening rates and immunity regardless of country of birth suggests that the previous strategies of risk-based screening based on country-level endemicity failed to adequately identify those with or at risk for HBV infection,” they wrote. “Interventions that couple universal HBV screening and vaccination are needed to reduce HBV-related morbidity and achieve elimination.”

Reference

^{Sumethasorn M, Wong C, Terrault N, Zhou K. COUNTRY-SPECIFIC SCREENING, PREVALENCE, AND IMMUNITY RATES FOR HEPATITIS B INFECTION IN THE UNITED STATES. Paper presented at: The Liver Meeting. Boston, MA. November 10 - 14, 2023.}