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Infectious Diseases in Refugee and Internationally Adopted Children
In this chapter, the infectious disease issues of 2 groups of immigrants are discussed: refugees and internationally adopted children. Refugees are noncitizen immigrants who are unable or unwilling to return to their country of origin because of persecution or a fear of persecution. Internationally adopted children are immigrants who are classified as orphans; most however are not truly orphaned but have been abandoned by or separated from their parents.
Since 2004 the number of refugee arrivals to the US has ranged from 22,405 to 74,602 per year, with 29,916 arriving in 2019. Of these, 13,264 (44%) were <20 years of age and 75% were ≥5 years of age. Nationalities of refugees coming to the US change each year with variations of policies and new conflicts. From 2000 to 2018, there was a diverse refugee population with refugees from Burma (16%), Iraq (13%), Somalia (10%), Bhutan (9%), Democratic Republic of the Congo (7%), Iran (6%), the Ukraine (5%), and Cuba (5%). With changes in US policies, the distribution shifted in 2019, with 84% of arriving refugees coming from just 5 countries: Congo (43%), Burma (16%), the Ukraine (15%), Eritrea (6%), and Afghanistan (4%).
Since 1999, more than 275,000 children have been internationally adopted in the US, with a peak of 22,990 children adopted in 2004. Since then, the numbers have steadily declined, with only 2971 children adopted in 2019. Over this period, a significant shift in the source countries and the ages of children adopted has occurred. In 2004, 83% of adopted children came from 5 countries: China (31%), Russia (26%), Guatemala (14%), South Korea (8%), and Kazakhstan (4%), and only 14% of children were ≥5 years of age. In contrast, 75% of internationally adopted children came from 9 countries in 2019: China (28%), the Ukraine (10%), Colombia (8%), India (8%), South Korea (6%), Bulgaria (4%), Haiti (4%), Nigeria (4%), and the Philippines (3%); the ages of these children has increased, with 53% being >5 years of age. In addition, nearly all children from China in recent years have had significant medical or developmental special needs, whereas in 2004 most children adopted from China were relatively healthy.
Because refugees and internationally adopted children come from resource-limited countries, healthcare providers should be cognizant of the global prevalence of infectious diseases that are seen less commonly in native-born North Americans. Both immigrant groups are at increased risk for common infectious diseases such as tuberculosis (TB), intestinal parasites, dermatologic infections, and infestations. In addition, infections with hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV), and Treponema pallidum (syphilis) are far more prevalent in the countries of immigrants where resources for screening and prevention are scarce compared with the US.
Refugee and internationally adopted children differ in terms of the general medical screening they receive before arrival in the US. First, most refugees receive organized screening evaluations, including a physical examination and assessment for TB, before emigration visas are issued. In contrast, only adoptees from certain countries with high rates of TB have been required to undergo this organized screening procedure for TB. Second, because medical screening for refugees usually is sponsored by responsible medical organizations, results of such testing typically are accurate. For international adoptees, results of serologic tests for HIV, syphilis, and HBV from country of origin typically are provided. When tests from countries with established screening programs (e.g., China and South Korea) have been repeated in the US, previous results generally have proven to be accurate. In other countries, results of tests either are not provided or the accuracy of testing is not known. Third, preventive measures such as immunizations, vitamin supplementation, and dental care are undertaken for most refugees, whereas in adoptees, preventive care is inconsistent. Fourth, differences in the types of infectious diseases also may distinguish refugees from adopted children. Although both populations are susceptible to a variety of infectious agents, because the countries of origin and the existing living conditions differ, refugee children are more likely to have been exposed to infections such as typhoid fever, malaria, filariasis, flukes, or schistosomiasis, which occur less commonly in internationally adopted children from countries outside Africa. Finally, programs have been established for pre-arrival treatment of refugees for intestinal parasites and malaria, while these programs do not exist for international adoptees.
Guidelines for Evaluation
With the high prevalence of infectious diseases in resource-limited countries, recommendations for screening tests are weighted toward infectious disease processes, but aspects of general health, including vision, hearing, dental, developmental, and mental health screenings, also should be included. Despite the healthy appearance of many immigrant children, refugee children should be evaluated within 90 days after arrival and internationally adopted children should be evaluated within 2 weeks after arrival to ensure that they have been or are screened properly and receive preventive healthcare services. Table 4.1 outlines the recommended screening tests for infectious diseases for refugee and internationally adopted children. The reader also is referred to pathogen-specific chapters.
TABLE 4.1
Recommended Screening Tests for Refugee and Internationally Adopted Children
| Test | Refugee Children | Internationally Adopted Children |
|---|---|---|
| Tuberculosis testing | All | All a |
| Hepatitis A virus serologic testing | Consider | Consider |
| Hepatitis B virus serologic testing Hepatitis B surface antigen (HBsAg) a Hepatitis B surface antibody (anti-HBs) Hepatitis B core antibody (anti-HBc) | All | All |
| Hepatitis C virus serologic testing | Risk Factors | All |
| Human immunodeficiency virus 1 and 2 serologic testing | ≥15 years of age and if risk factors | All a |
| Syphilis serologic testing (testing strategy per local protocols) | ||
| Nontreponemal test (RPR, VDRL, or ART) Treponemal test (TPPA, MHA-TP, or FTA-ABS) | ≥15 years of age and if risk factors≥15 years of age and if risk factors | AllAll |
| Stool examination | ||
| Microscopic evaluation for ova and parasites (3 specimens) Giardia duodenalis and Cryptosporidium antigen (1 specimen) | All b All b | AllAll |
| Complete blood count and differential | All | All |
| Urinalysis | All | Not recommended |
ART, automated reagin test; FTA-ABS, fluorescent treponemal antibody absorption; MHA-TP, microhemagglutination- Treponema pallidum ; RPR, rapid plasma reagin; TPPA, Treponema pallidum particle agglutination; VDRL, Venereal Disease Research Laboratory.
a Consider reassessing 3–6 months after arrival.
b All should be screened if no presumptive treatment occurred before arrival to the US. See Centers for Disease Control and Prevention: http://www.cdc.gov/immigrantrefugeehealth/guidelines/domestic/intestinal-parasites-domestic.html .
Hepatitis A
Virtually all inhabitants of resource-poor countries will have contracted hepatitis A virus (HAV) by early adulthood. , With HAV vaccine recommended for all US children ≥12 months of age, immunoglobulin G (IgG) anti-HAV testing in children ≥1 year of age should be considered for all immigrants to determine which children should be immunized. Screening for immunoglobulin M (IgM) anti-HAV can be useful to identify the child with acute HAV infection so that secondary prevention through HAV vaccine can be provided to unvaccinated family members and close contacts. Because HAV infection is anicteric in young children, and because most young children are asymptomatic, the only way to identify children who may shed HAV for months is by screening with an IgM anti-HAV test. Even in the absence of jaundice, symptoms of HAV infection should prompt evaluation for viral hepatitis in recently arrived immigrants or adoptees.
Hepatitis B
Routine screening for hepatitis B (HBV) infection is recommended for all refugees and internationally adopted children. Early identification of HBV infection is important to provide appropriate management and to initiate vaccination of unvaccinated household contacts and caregivers. Prevalence of chronic HBV infection varies by region, and rates of infection in refugee and internationally adopted children mirror the rates of infection in their country of origin. Children typically acquire HBV at or before birth, although bloodborne and horizontal transmissions also have occurred. The prevalence of HBV in refugee children varies by country, ranging from 0%–5%. Refugee children in many countries now receive hepatitis B testing and, if uninfected, hepatitis B vaccine before departure to the US. In internationally adopted children, the prevalence of chronic HBV infection has decreased from a high of 20% in Romanian adoptees from the early 1990s to 1%–5% in more recent studies.
HBV screening tests, including for HBV surface antigen (HBsAg) and antibodies to surface (anti-HBs) and to core antigen (anti-HBc), are recommended in the medical evaluation of internationally adopted children and refugees. , , All 3 tests should be performed to determine whether the child is immune as a result of immunization, has recovered from infection, or has acute or chronic hepatitis B. Common patterns of the hepatitis B serology profile are shown in Chapter 213 . In a child who is found to be HBsAg positive, testing should be repeated 6 months later; if HBsAg persists for ≥6 months, the child has chronic hepatitis B infection. If the child no longer has HBsAg and has developed anti-HBs, the child had acute infection, has recovered, and is no longer able to transmit HBV to others. Children with acute or chronic HBV infection (positive HBsAg) can transmit HBV to others and should have additional tests performed, including HBV e antigen (HBeAg), HBV e antibody (HBeAb), quantitative HBV polymerase chain reaction (PCR), α-fetoprotein, and serum hepatic enzyme levels. HBsAg-positive children should be followed by a hepatologist or infectious diseases specialist familiar with management and treatment of chronic hepatitis B infection. For children with negative test results initially, some experts recommend repeat testing for HBV approximately 6 months after arrival in the US to exclude infection just before arrival. Children with acute or chronic HBV infection also should have serologic testing for HAV (to determine the need for vaccination) and HCV (for management and treatment considerations). Children who have received <3 documented doses of hepatitis B vaccine should complete the 3-dose series even if serologic testing for hepatitis B surface antibody is positive.
Vaccination of household contacts of children with acute or chronic HBV (HBsAg-positive children) must occur promptly. Epidemiologic studies have demonstrated that up to 20% of unvaccinated household contacts of HBV cases become HBsAg positive within ≥5 years of exposure within the home, , and transmission of HBV from newly adopted children to their parents is well documented.
Hepatitis C
Hepatitis C (HCV) testing is recommended for internationally adopted children and refugee children with risk factors for HCV. , Few data exist for either group of children; the prevalence of HCV in internationally adopted children from one study was <1%. The appropriate testing sequence is serologic testing initially, and if the antibody test result is positive, then HCV PCR is performed to confirm active infection. Children with HCV infection should be immunized for HAV and HBV if they are nonimmune or unimmunized for these viruses and should be referred to a hepatologist or infectious disease specialist familiar with management and treatment of HCV. Antiviral therapies have been licensed by the US Food and Drug Administration down to 3 years of age.
Human Immunodeficiency Virus-1 and Human Immunodeficiency Virus-2 Infection
Refugees are not tested routinely for HIV pre-departure. After arrival in the US, HIV testing is recommended for refugee children ≥13 years of age and is encouraged for younger children.
In contrast, most internationally adopted children have been tested for HIV-1 anti-IgG by enzyme immunoassay (EIA) in their birth country. Although reports of HIV infection in internationally adopted children are rare, , , routine screening by EIA is recommended for all internationally adopted children on arrival in the US. Positive or indeterminate results should be resolved with use of HIV DNA PCR. If clinical suspicion of HIV infection exists, HIV DNA PCR testing should be considered if the result of antibody testing by EIA is negative. Antibody retesting ≥6 months after arrival in the US should be considered. An increasing number of children known to have HIV infection are being adopted. Most children with HIV have had their infection diagnosed in infancy and are already being treated with antiretroviral medications. Thus, clinicians should be prepared to provide care and resources for children arriving in the US with HIV infection.
Pre-adoptive testing for HIV-2 infection is not performed routinely. HIV-2 infection is prevalent in some African nations and is now recognized on several other continents; perinatal transmission appears to be limited. Symptoms suggestive of HIV infection in a child with negative EIA results for HIV-1 should prompt testing for HIV-2.
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