The United States has historically been called the land of opportunity, a place where people of any faith, ethnicity, or lifestyle can live without fear of persecution while pursuing economic prosperity. Enticed by these personal and financial freedoms, more than 35 million immigrants currently reside in America.1 However, with about 45% of the global population living in areas with a high prevalence of chronic hepatitis B (CHB), vaccination, screening, and awareness efforts for immigrants are vital to public health (Table 1).2

Since 1991, routine hepatitis B virus (HBV) vaccination has been recommended for all newborns in the United States, which has led to a significant decline in domestically transmitted cases.3 But these requirements either do not exist or were only recently introduced abroad, so prevalence rates are higher among certain foreign-born individuals. Of the more than 35 million immigrants currently living in the United States, an estimated 1.6 million (4.5%) are infected with CHB.1 Consequently, these individuals experience a disproportionate mortality rate: Approximately 95% of CHB-related deaths in the United States occur among immigrants.3

Table 1. Global Burden of CHB
Prevalence of CHB % of Global Population Lifetime Risk for Infection Common Route of Transmission Common Age of Acquired Infection
High (≥8%) 45% >60% Mother-to-child; percutaneous or mucosal Infections commonly occur at birth and in early childhood
Intermediate (2%-7%) 43% 20%-60% Mother-to-child; percutaneous or mucosal; sexual contact Infections commonly occur in all age groups
Low (<2%) 12% <20% Percutaneous or mucosal; sexual contact Infections commonly occur in adult risk groups
From reference 2.

These high CHB rates, coupled with concerns over the estimated 1.4 million undiagnosed cases of CHB in the United States,4 led the Centers for Disease Control and Prevention (CDC) to recommend screening for all individuals born in areas of intermediate or high CHB endemicity (ie, regions with CHB prevalence rates ≥2%).5 Countries with large immigration rates to the United States and high CHB endemicity include the Philippines, China, Vietnam, and Korea; intermediate endemicity regions include the Dominican Republic and Haiti (Figure).3

Ke-Qin Hu, MD

Ke-Qin Hu, MD, director, Hepatology Services, professor of clinical medicine, University of California at Irvine, discussed the progress he has seen since emigrating from China to the United States. “The first universal HBV vaccine was launched in Taiwan around 1985; since then, the vaccine has been readily available and effective in most urban areas throughout Asia. Many studies have demonstrated that universal HBV vaccination can effectively reduce the prevalence of CHB and related primary liver cancer. Thus, HBV vaccination is considered the first [HBV-related] cancer-preventing vaccine for humans,” he said.

Individuals applying for US immigrant visas are screened overseas for communicable diseases of public health significance, such as tuberculosis or syphilis,6 and positive results may preclude their ability to enter the country.7 Applicants also are screened for vaccine-preventable diseases, but only proof of the first dose is required to achieve permanent residence (Table 2).7 As a result, Dr. Hu said that increasing awareness, immunizations, and screening practices among primary care physicians remains an important step in the management of this disease because these clinicians often serve as the first and only line of medical care.

Table 2. Vaccination Requirements for US Immigration
Currently, immigrants to the United States must show proof of vaccination against the following:
  • Haemophilus influenzae type b
  • Pneumococcal disease
  • Hepatitis A
  • Polio
  • Influenza
  • Rotavirus
  • Hepatitis B*
  • Rubella
  • Mumps
  • Varicella
  • Measles
  • Tetanus and diphtheria
  • Pertussis
  • Meningococcal disease
* Although the hepatitis B shot is part of a series, only a single dose is required for immigration into the United States.
From reference 7.

“Some primary care doctors are doing well with screening, others need to catch up with the literature about who to screen and why. Effective treatment reduces HBV-related complications, so we must get patients screened and access to care,” said Dr. Hu.

Widespread initiatives such as World Hepatitis Day have increased the visibility and awareness of viral hepatitis, but disparities remain. Imported cases of CHB remain common,3 and if left undiagnosed, these individuals may transmit the virus to those close to them. Physicians can reduce this risk by adhering to the CDC’s 2008 recommendations for screening foreign-born individuals and educating patients during appointments.

Dr. Hu recalled one such instance that reflects the importance of screening immigrants and encouraging regular health care visits. “I recently had a patient who was in the United States for nearly 30 years without seeing any doctors, until he developed some symptoms and was diagnosed with CHB, cirrhosis, and liver cancer. The first time he heard about CHB was when we told him he had cancer,” said Dr. Hu.

Figure. Immigration regions with noteworthy HBsAg prevalence between 1974 and 2008.
CHB, chronic hepatitis B; HBsAg, hepatitis B surface antigen
From reference 3.


  1. Rossi C, Shrier I, Marshall L, et al. Seroprevalence of chronic hepatitis B virus infection and prior immunity in immigrants and refugees: a systematic review and meta-analysis. PLoS One. 2012;7(9):e44611.
  2. Greenaway C, Narasiah L, Plourde P, et al. Hepatitis B: evidence review for newly arriving immigrants and refugees. CMAJ. 2011;183(12):1-16.
  3. Mitchell T, Armstrong GL, Hu DJ, et al. The increasing burden of imported chronic hepatitis B—United States, 1974-2008. PLoS One. 2011;6(12):e27717.
  4. Cohen C, Holmberg SD, McMahon BJ, et al. Is chronic hepatitis B undertreated in the United States? J Viral Hepat. 2011;18(6): 377-383.
  5. Centers for Disease Control and Prevention. Recommendations for identification and public health management of persons with chronic hepatitis B virus infection. MMWR. 2008;57(RR-8):1-28.
  6. U.S. Citizenship and Immigration Services.​files/​form/​i-693.pdf. Accessed April 27, 2013.
  7. Centers for Disease Control and Prevention.​immigrantrefugeehealth/​exams/​medical-examination-faqs.html#6. Accessed April 27, 2013.