Stacene R. Maroushek
More than 210,000 foreign-born children (≤16 yr old) enter the United States each year as asylees (asylum seekers), refugees, and immigrants, including international adoptees (see Chapter 8 ). This number does not include undocumented children living and working in the United States, the U.S.-born children of foreign-born parents, or the approximately 2.7 million nonimmigrant visitors ≤16 yr old who legally enter the United States annually with temporary visas. With the exception of internationally adopted children, pediatric guidelines for screening these newly arrived children are sparse. The diverse countries of origin and patterns of infectious disease, the possibility of previous high-risk living circumstances (e.g., refugee camps, orphanages, foster care, rural/urban poor), the limited availability of reliable healthcare in many economically developing countries, the generally unknown past medical histories, and interactions with parents who may have limited English proficiency and/or varied educational and economic experiences, make the medical evaluation of immigrant children a challenging but important task.
Before admission into the United States, all immigrant children are required to have a medical examination performed by a physician designated by the U.S. Department of State in their country of origin . This examination is limited to completing legal requirements for screening for certain communicable diseases and examination for serious physical or mental problems that would prevent issuing a permanent residency visa. This evaluation is not a comprehensive assessment of the child's health, and except in limited circumstances, laboratory or radiographic screening for infectious diseases is not required for children <15 yr old. After entry into the United States, health screenings of refugees, but not other immigrants, are recommended to be done by the resettlement state. There is limited tracking of refugees as they move to different cities or states. Thus, many foreign-born children have had minimal pre- or postarrival screening for infectious diseases or other health issues.
Immunization requirements and records also vary depending on entry status. Internationally adopted children who are younger than 10 yr are exempt from Immigration and Nationality Act regulations pertaining to immunization of immigrants before arrival in the United States. Adoptive parents are required to sign a waiver indicating their intention to comply with U.S.-recommended immunizations, whereas older immigrants need only show evidence of up-to-date, not necessarily complete, immunizations before application for permanent resident (green card) status after arrival in the United States.
Infectious diseases are among the most common medical diagnoses identified in immigrant children after arrival in the United States. Children may be asymptomatic; therefore, diagnoses must be made by screening tests in addition to history and physical examination. Because of inconsistent perinatal screening for hepatitis B and hepatitis C viruses, syphilis, and HIV, and the high prevalence of certain intestinal parasites and tuberculosis, all foreign-born children should be screened for these infections on arrival in the United States. Table 10.1 lists suggested screening tests for infectious diseases. Table 10.2 lists incubation periods of common internationally acquired diseases. In addition to these infections, other medical and developmental issues, including hearing, vision, dental, and mental health assessments; evaluation of growth and development; nutritional assessment; lead exposure risk; complete blood cell count with red blood cell indices; microscopic urinalysis; newborn screening (this could also be done in non-neonates) and/or measurement of thyroid-stimulating hormone concentration; and examination for congenital anomalies (including fetal alcohol syndrome) should be considered as part of the initial evaluation of any immigrant child.*
Table 10.2
Incubation Periods of Common Travel-Related Infections*
* Diseases that commonly have variable incubation periods are shown more than once. However, most diseases may rarely have an atypical incubation period, and this is not shown here.
HIV, Human immunodeficiency virus.
From Freedman DO: Infections in returning travelers. In Bennett JE, Dolin R, Blaser MJ, editors: Mandell, Douglas, and Bennett's principles and practice of infectious diseases, ed 8, Philadelphia, 2015, Elsevier (Table 324-2).
Children should be examined within 1 mo of arrival in the United States, or earlier if there are immediate health concerns, but foreign-born parents may not access the healthcare system with their children unless prompted by illness, school vaccination, or other legal requirements. It is important to assess the completeness of previous medical screenings at any first visit with a foreign-born child.
Clinicians should be aware of potential diseases in high-risk immigrant children and their clinical manifestations. Some diseases, such as central nervous system cysticercosis, may have incubation periods as long as several years, and thus may not be detected during initial screening. On the basis of findings at the initial evaluation, consideration should be given to a repeat evaluation 6 mo after arrival. In most cases, the longer the interval from arrival to development of a clinical syndrome, the less likely the syndrome can be attributed to a pathogen acquired in the country of origin.
See also Chapter 385 .
The prevalence of hepatitis B surface antigen (HBsAg) in refugee children ranges from 4–14%, depending on the country of origin, age, and year studied. Prevalence of markers of past hepatitis B virus (HBV) infection is higher. HBV infection is most prevalent in immigrants from Asia, Africa, and some countries in Central and Eastern Europe, as well as the former Soviet Union (e.g., Bulgaria, Romania, Russia, Ukraine), but also occurs in immigrants born in other countries. All immigrant children, even if previously vaccinated, coming from high-risk countries (HBsAg seropositivity >2%) should undergo serologic testing for HBV infection, including both HBsAg and antibody to HBsAg (anti-HBs), to identify current or chronic infection, past resolved infection, or evidence of previous immunization. Because HBV has a long incubation period (6 wk–6 mo), the child may have become infected at or near the time of migration, and initial testing might be falsely negative. Therefore, strong consideration should be given to a repeated evaluation 6 mo after arrival for all children, especially those from highly endemic countries. Chronic HBV infection is indicated by persistence of HBsAg for >6 mo. Children with HBsAg-positive test results should be evaluated to identify the presence of chronic HBV infection, which occurs in >90% of infants infected at birth or in the 1st yr of life and in 30% of children exposed at ages 1-5 yr. Once identified as being infected, additional testing should be done to assess for biochemical evidence of severe or chronic liver disease or liver cancer.
See Chapter 385 .
See also Chapter 385 .
The decision to screen children should depend on history (e.g., receipt of blood products; traditional percutaneous procedures such as tattooing, body piercing, circumcisions, or other exposures to reused, unsterile medical devices) and the prevalence of hepatitis C virus (HCV) infection in the child's country of origin. Children from Eastern Mediterranean and Western Pacific countries, Africa, China, and Southeast Asia should be considered for HCV infection screening. All children coming from Egypt, which has the highest known HCV seroprevalence (12% nationally and 40% in some villages), should be tested for hepatitis C.
Fecal examinations for ova and parasites (O&P) by an experienced laboratory will identify a pathogen in 8–86% of immigrants and refugees The prevalence of intestinal parasites varies by country of origin, time period when studied, previous living conditions (including water quality, sanitation, and access to footwear) and age, with toddler/young school-age children being most affected. If documented predeparture treatment was given, an eosinophil count should be performed. An absolute eosinophil count of >400 cells/µL, if persistently elevated for 3-6 mo after arrival, should prompt further investigation for tissue-invasive parasites such as Strongyloides (see Chapter 321 ) and Schistosoma (Chapter 326 ) species (if no predeparture praziquantel given). If no documented predeparture treatment was given, 2 stool O&P specimens obtained from separate morning stools should be examined by the concentration method, and an eosinophil count performed. If the child is symptomatic, including evidence of poor physical growth, but no eosinophilia is present, a single stool specimen should also be sent for Giardia lamblia (see Chapter 308.1 ) and Cryptosporidium parvum (Chapter 309 ) antigen detection. All potentially pathogenic parasites found should be treated appropriately. All nonpregnant refugees >2 yr of age coming from sub-Saharan Africa and Southeast Asia should be presumptively treated with predeparture albendazole.
See also Chapter 242 .
Tuberculosis (TB) commonly is encountered in immigrants from all countries because Mycobacterium tuberculosis infects approximately 30% of the world's population. Latent TB infection rates can be up to 60% in some refugee children from North Africa and the Middle East. Prior to 2007, chest radiographs or tuberculin skin tests were generally not administered in children <15 yr of age, and reports indicate that 1–2% of these unscreened children may enter the United States with undiagnosed active TB disease.
Since 2007, TB Technical Instructions for Medical Evaluation of Aliens have required that children ages 2-14 yr undergo a TB skin test or interferon-γ release assay if they are medically screened in countries where the TB rate is ≥20 cases per 100,000 population. If the testing is positive, a chest radiograph is required. If the chest film suggests TB, cultures and 3 sputum smears are required, all before arrival in the United States. Check with the Centers for Disease Control and Prevention, Division of Global Migration and Quarantine, for the latest information (www.cdc.gov/ncidod/dq/technica.htm ).
See Chapter 245 .
See Chapter 302 .
See Chapter 197 .
Immigrant children and adolescents should receive immunizations according to the recommended schedules in the United States for healthy children and adolescents. Some immigrants will have written documentation of immunizations received in their birth or home country. Although immunizations such as bacille Calmette-Guérin, diphtheria and tetanus toxoids and pertussis (DTP), poliovirus, measles, and HBV vaccines often are documented, other immunizations, such as Haemophilus influenzae type b, mumps, and rubella vaccines, are given less frequently, and Streptococcus pneumoniae , human papillomavirus, meningococcal, and varicella vaccines are given rarely. When doubt exists, an equally acceptable alternative is to reimmunize the child. Because the rate of more serious local reactions after diphtheria, tetanus toxoid, and acellular pertussis vaccine increases with the number of doses administered, serologic testing for antibody to tetanus and diphtheria toxins before reimmunizing, or if a serious reaction occurs, can decrease risk.
In children older than 6 mo with or without written documentation of immunization, testing for antibodies to diphtheria and tetanus toxoid and poliovirus may be considered to determine whether the child has protective antibody concentrations. If the child has protective concentrations, the immunization series should be completed as appropriate for that child's age. In children older than 12 mo, measles, mumps, rubella, and varicella antibody concentrations may be measured to determine whether the child is immune; these antibody tests should not be performed in children younger than 12 mo because of the potential presence of maternal antibody.