Gauging the Influence of Immigration on Hepatitis B in the United States

The prevalence of hepatitis B virus (HBV) infection in the US is significantly higher than previously estimated, according to a new modeling study which accounts for HBV infection and control in the origin countries of immigrants to the US.

"In the US, previous studies attempted to quantify the impact of immigration, but these studies were limited by utilizing immigrant HBV prevalence estimates that were non-representative of the general population at the time of the study and incorporated studies that reported HBV prevalence in different age groups across countries—most often adults only—applied to the countries' population," observed lead author Devin Razavi-Shearer, Center for Disease Analysis Foundation, Lafayette, CO, and colleagues.

"We designed the current methodology to overcome these shortcomings by utilizing modeling to estimate the impact of immigration on the HBV prevalence in Western countries," Razavi-Shearer and colleagues indicated.

The investigators utilized a dynamic Markov model, the PRoGReSs model from the Polaris Observatory, which maintains 166 country-specific HBV disease burden models that are updated annually. The PRoGReSs model considers vertical and horizontal transmission, the impact of HBV prophylaxis programs, disease progression, all-cause and liver-related mortality, and the impact of HBV treatment on disease progression and transmission.

The investigators applied the model to immigrants receiving lawful permanent resident status in the US, which has been collated by country of birth, age, and sex since 1900. They limited their cohort to lawful permanent residents, they explain, as these individuals are most likely to remain in the country permanently, and are the only group for which reliable data are consistently available.

The model estimates that in 2020 there were 35,000 chronic HBV-positive individuals among those gaining lawful permanent resident status. Aside from HBV among immigrants, the US was estimated to have over 8000 acute and over 1400 chronic HBV infections in 2020.

In contrast to the nationally reported estimate of 0.32% (0.24-0.41%) prevalence of HBV infections in the US, this modeling study estimates an HBV prevalence of 0.55% (0.41-0.77). Razavi-Shearer and colleagues also estimate that if non-immigrants, including temporary workers and undocumented immigrants are included, the overall prevalence is approximately 0.63% (0.48-0.85).

The model estimates that in 2020, 76% of all immigrants with chronic HBV were born in 20 countries, with almost 40% from the Philippines, China and Vietnam. When Global Burden of Disease regions are examined, 74% of all cases among immigrants are from 5 regions: Asia Southeast, East and South, the Caribbean, and Sub-Saharan Africa West.

The investigators point out that the current recommendation to screen immigrants for HBV arriving from countries with a prevalence over 2 percent excludes an estimated 18% of immigrants with HBV, or over 253,000 cases of infection in 2020.

Razavi-Shearer and colleagues prefer, instead, the recent CDC draft recommendations for universal screening of adults for HBV. "However, it should be ensured that there are adequate resources for outreach, education, screening, linkage to care and vaccination for immigrant communities," they suggest.

"As they face different cultural and linguistic barriers than the general population and they have a higher burden, they should be prioritized for funding focus," Razavi-Shearer and colleagues advise.