In the past 15 years, >260,000 children have come to the United States to join their families through international adoption. Families traveling to unite with their adopted child, siblings who wait at home for the child’s arrival, extended family members, and childcare providers are all at risk for acquiring infectious diseases secondary to travel or resulting from contact with the newly arrived child. International adoptees may be underimmunized and are at increased risk for infections such as measles, hepatitis A, and hepatitis B because of crowded living conditions, malnutrition, lack of clean water, lack of immunizations, and exposure to endemic diseases not commonly seen in the United States. Challenges in providing care to internationally adopted children include the absence of a complete medical history, lack of availability of a biological family history, questionable reliability of immunization records, variation in preadoption living standards, varying disease epidemiology in the countries of origin, the presence of previously unidentified medical problems, and the increased risk for developmental delays and psychological issues in these children.
Travel Preparation for Adoptive Parents and their Families
A pretravel clinic visit is strongly recommended for prospective adoptive parents. In preparation, the travel health provider must know the disease risks in the adopted child’s country of origin and the medical and social histories of the adoptee (if available), as well as which family members will be traveling, their immunization and medical histories, the season of travel, the length of stay in the country, and the itinerary while in country. Family members who remain at home, including extended family, should be current on their routine immunizations. Protection against measles, varicella, tetanus, diphtheria, pertussis, polio, and hepatitis A (HAV), as well as hepatitis B (HBV) if the adoptee has known infection or if the family is traveling to a country with high or intermediate levels of endemic HBV infection, must be ensured for all age-eligible people who will be in the household or in close contact by providing care for the adopted child.
An accelerated schedule of doses may be used to complete a vaccine series as long as minimum ages and dose intervals are followed. Measles immunity or 2 doses of measles-mumps-rubella (MMR) vaccine separated by ≥28 days should be documented for all people born in or after 1957. Varicella vaccine should be given to those born in or after 1980 without a history of varicella disease, documented immunity (serology), or documentation of 2 doses of varicella vaccine. Adults who have not received the tetanus-diphtheria-acellular pertussis (Tdap) vaccine, including adults >65 years old, should receive a single dose of Tdap to protect against Bordetella pertussis in addition to tetanus and diphtheria. Unprotected family members and close contacts of the adopted child should be immunized against HAV before the child’s arrival. Most adult family members and caretakers will need to be immunized with hepatitis B vaccine if the adoptee has a known HBV infection, since it has only been routinely given since 1991.
If the adopted child is from a polio-endemic area, family members and caretakers should ensure they have completed the recommended age-appropriate polio vaccine series. A one-time inactivated polio booster for adults who have completed the primary series in the past is recommended if they are traveling to these areas and can be considered for adults who remain at home but who will be in close contact caring for the child. Additional polio vaccination requirements for long-term travelers (staying >4 weeks) and residents departing from countries with polio transmission may affect travel (see Chapter 4, Poliomyelitis).
Prospective adoptive parents and any children traveling with them should receive advice on travel safety, food safety, immunization, malaria prophylaxis, diarrhea prevention and treatment, and other travel-related health issues, as outlined elsewhere in this book.
Overseas Medical Examination of the Adopted Child
All immigrants, including children adopted internationally by US citizens, must undergo a medical examination in their country of origin, performed by a physician designated by the Department of State. Additional information about the medical examination for internationally adopted children is available on the Department of State website at https://travel.state.gov/content/travel/en/Intercountry-Adoption/Adoption-... and https://eforms.state.gov/Forms/ds1981.pdf. Prospective adoptive parents should not rely on this overseas medical examination to detect all possible disabilities and illnesses, as the purpose of the medical examination is to identify applicants with inadmissible health-related conditions. To understand more about possible health concerns for an individual child, prospective adoptive parents should consider a preadoption medical review with a pediatrician who is familiar with the health issues of internationally adopted children to review the available medical history and vaccination record for the child. This preadoption medical review can prepare parents and providers for potential health issues that may occur with internationally adopted children, whose living conditions in their country of origin may differ significantly from those in the United States. Prospective adoptive parents can then proactively arrange and schedule any recommended follow-up after arrival home, including the initial follow-up medical examination that is recommended within 2 weeks of arrival to the United States (for additional information, see www.cdc.gov/immigrantrefugeehealth/adoption/finding-doctor.html). Although the overseas medical examination is not a comprehensive medical review, adoptive parents may be able to provide the results of the overseas examination, recorded on the Department of State medical forms, to the clinicians at the initial follow-up medical examination.
Follow-Up Medical Examination After Arrival in the United States
Adopted children should have a complete medical examination within 2 weeks of arrival in the United States or earlier if the child has fever, anorexia, diarrhea, vomiting, or other medical concerns. In addition, all children should receive a developmental screening by an experienced clinician to determine if immediate referrals should be made for more detailed neurodevelopmental examination and therapies. Further evaluation will depend on the country of origin, the age of the child, previous living conditions, nutritional status, developmental status, and the adoptive family’s specific questions. Concerns raised during the preadoption medical review may dictate further investigation.
Screening for Infectious Diseases
Screening recommendations for some infectious diseases vary by organization. The current panel of tests for infectious diseases recommended by the American Academy of Pediatrics (AAP) for screening internationally adopted children is as follows:
- Hepatitis A serologic testing (IgG and IgM)
- Hepatitis B serologic testing
- Hepatitis C serologic testing
- Syphilis serologic testing (treponemal and nontreponemal testing)
- HIV 1 and 2 serologic testing (antigen/antibody)
- Complete blood cell count with differential and red blood cell indices
- Stool examination for ova and parasites (3 specimens)
- Stool examination for Giardia intestinalis and Cryptosporidium antigen (1 specimen)
- TB testing:
- For children <2 years of age, tuberculin skin test (TST) is preferred
- For children ≥2 years of age, either interferon-γ release assay (IGRA) or TST can be used (for those previously vaccinated with BCG, IGRA is preferred)
- Repeat testing should be done 3–6 months later, if initial testing is negative
Additional screening tests may be useful, depending on the child’s country of origin or specific risk factors. These screens may include Chagas disease serologic tests, malaria smears or PCR, and serologic testing for schistosomiasis, strongyloidiasis, and filariasis. Cases of reportable diseases should be reported to the state or local health department.
Gastrointestinal parasites are commonly seen in international adoptees, but the prevalence varies by birth country and age. The highest rates of infection have been reported from Ukraine and Ethiopia and increase with older age.
Giardia intestinalis is the most common parasite identified. Three stool samples collected in the early morning, 2–3 days apart, and placed in a container with preservative are recommended for ova and parasite analysis. Because routine examination of stool for ova and parasites is unlikely to include testing for Cryptosporidium , health care providers should specifically request Cryptosporidium testing.
Although theoretically possible, transmission of intestinal parasites from internationally adopted children to family and school contacts has not been reported; however, good hand hygiene is recommended to prevent infection. Stool samples should be tested for enteric pathogens for any child with fever and diarrhea. If a culturable enteric pathogen is detected, samples should be cultured to determine antimicrobial susceptibility. Unlike refugees, internationally adopted children are not treated for parasites before departure.
Screening asymptomatic people for hepatitis A is generally not recommended; however, clinicians may decide to test internationally adopted children for anti-HAV IgG and IgM to identify those who may be acutely infected and shedding virus and to make decisions regarding hepatitis A vaccination.
In 2007 and early 2008, multiple cases of hepatitis A secondary to exposure to newly arrived internationally adopted children were reported in the United States. Some of these cases involved extended family members who were not living in the household. Identification of acutely infected toddlers new to the United States is necessary to prevent further transmission. If a child is found to have an acute infection, hepatitis A vaccine or immunoglobulin can be given to close contacts to prevent infection. In addition, it is cost effective to identify children with past infection with serologic testing, since they would not need to receive the hepatitis A vaccine.
All internationally adopted children should be screened for HBV infection with serologic tests for hepatitis B surface antigen (HBsAg), hepatitis B surface antibody, and hepatitis B core antibody to determine past infection, current infection, or protection due to vaccination. Because of widespread use of the hepatitis B vaccine, the prevalence of HBV infection has decreased over the years. HBV infection has been reported in 1%– 5% of newly arrived adoptees. Children found to be positive for HBsAg should be retested 6 months later to determine if the child has a chronic infection. Results of a positive HBsAg test should be reported to the state health department.
HBV is highly transmissible within the household. All members of households adopting children with chronic HBV infection must be immunized. Children with chronic HBV infection should receive additional tests for HBV e antigen, HBV e antibody, hepatitis D virus antibody, viral load, and liver function. They should be vaccinated for hepatitis A if they are not immune. They should also have a consultation with a pediatric gastroenterologist.
Although not currently recommended by CDC or AAP, repeat screening at 6 months after arrival may be considered for all children who initially test negative for hepatitis B surface antibody.
Routine screening for hepatitis C virus (HCV) may be considered, since most children with HCV infection are asymptomatic, screening for risk factors is not possible, and close follow-up of infected patients is needed to identify long-term complications. Antibody testing should be used for screening. Since maternal antibody may be present in children <18 months of age, PCR testing should be done if the antibody test is positive. Children with HCV infection should be referred to a gastroenterologist for further evaluation, management, and treatment.
Screening for Treponema pallidum is recommended for all internationally adopted children. Initial screening is done with both nontreponemal and treponemal tests. Treponemal tests remain positive for life in most cases even after successful treatment, and are specific for treponemal diseases, which include syphilis and other diseases (such as yaws, pinta, and bejel) that can be seen in some countries. In children with a history of syphilis, the child’s initial evaluation, treatment (antibiotic type and treatment duration), and follow-up testing are rarely available; therefore, a full evaluation for disease must be undertaken and antitreponemal treatment given depending upon the results.
HIV screening is recommended for all internationally adopted children. Positive HIV antibodies in children aged <18 months may reflect maternal antibody and not infection. PCR assay for HIV DNA will confirm the diagnosis in the infant or child. Standard screening for HIV is with ELISA antibody testing, but some experts recommend PCR for any infant aged <6 months on arrival. If PCR testing is done, 2 negative results from assays administered 1 month apart, at least one of which is done after the age of 4 months, are necessary to exclude infection. Children with HIV infection should be referred to a specialist. Some experts recommend repeating the screen for HIV antibodies 6 months after arrival if the initial testing is negative.
Other Sexually Transmitted Infections
Although routine screening for sexually transmitted infections beyond syphilis and HIV is not recommended, some experts will screen all children older than 5 years of age for chlamydia and gonorrhea. In addition, if there is any question or concern of sexual abuse, chlamydia and gonorrhea screening should be done for a child of any age.
Screening for Chagas should be considered for children arriving from countries endemic for the disease. Chagas disease is endemic throughout much of Mexico, Central America, and South America (see Chapter 4, Trypanosomiasis, American [Chagas Disease]).
The risk of Chagas disease varies by region within endemic countries. Although the risk of Chagas disease is likely low in adopted children from endemic countries, treatment of infected children is effective. Serologic testing when the child is aged 9–12 months will avoid possible false-positive results from maternal antibody. Testing by PCR can be done in children <9 months of age. Children testing positive for Chagas disease should be referred to a specialist for further evaluation and management.
Routine screening for malaria is not recommended for internationally adopted children. However, thick and thin malaria smears should be obtained immediately for any febrile child or child symptomatic with splenomegaly who has arrived from a malaria-endemic area (see Chapter 4, Malaria). Rapid diagnostic tests (RDTs) for malaria may be useful to decrease the amount of time that it takes to determine that a patient is infected with malaria, but microscopy should be used to confirm the results and determine the degree of parasitemia.
PCR testing may be useful to confirm the species of parasite after the diagnosis has been established by either smear microscopy or a RDT. Of note, asymptomatic children with splenomegaly need a workup for this condition. This workup should include antibody titers for malaria, since asymptomatic children with splenomegaly due to repeated malaria infections may have high titers but negative smears.
Internationally adopted children are at 4–6 times the risk for TB than their US-born peers. Screening for TB is an integral part of the overseas medical examination, and positive results from this screening on the Department of State medical forms may be available from adoptive parents (if they retained a copy) or with the local health department. If overseas screening results are not available, all internationally adopted children should be screened for TB after arriving in the United States, and any cases should be reported to the state health department.
To screen for TB, AAP recommends a TST for children <2 years of age. For children ≥2 years of age, either IGRA or a TST can be used. For those previously vaccinated with BCG, IGRAs appear to be more specific than the TST for Mycobacterium tuberculosis infection. For children who initially test negative for TB, repeat testing is recommended 3–6 months after arrival.
If the TST or IGRA is positive for TB, the child has TB infection and an additional evaluation needs to be done to determine if the child has latent TB infection (LTBI) or TB disease. Additional information is available at www.cdc.gov/tb/topic/reatment/ltbi.htm.
If a child has evidence of TB disease, consultation with an infectious disease expert is recommended.
A complete blood count with a differential should be drawn for all internationally adopted children. An eosinophil count >450 cells/mm3 in an internationally adopted child may warrant further evaluation. Intestinal parasite screening will identify some helminths that may cause eosinophilia. Further investigation of the eosinophilia might include serologic evaluation for Strongyloides stercoralis, Toxocara canis, Ancylostoma spp., and Trichinella spiralis . For children arriving from countries endemic for Schistosoma spp. and filariasis, serologic testing should be done for these diseases as well.
Screening for Noninfectious Diseases
Several screening tests for noninfectious diseases should be performed in all or in select internationally adopted children. All children should have a complete blood count with a differential, hemoglobin electrophoresis, and G6PD deficiency screening. Serum levels of thyroid-stimulating hormone and lead should be measured in all internationally adopted children. Testing for serum levels of iron, iron-binding capacity, transferrin, ferritin, and total vitamin D 25-hydroxy should be considered. All children should have vision and hearing screening and a dental evaluation. In certain circumstances, neurologic and psychological testing may also be considered.
The US Immigration and Nationality Act requires that any person seeking an immigrant visa for permanent residency must show proof of having received the Advisory Committee on Immunization Practices (ACIP)-recommended vaccines before immigration (www.cdc.gov/vaccines/schedules/hcp/imz/child-adolescent.html). This requirement applies to all immigrant infants and children entering the United States, but internationally adopted children aged <10 years are exempt from the overseas immunization requirements. Adoptive parents are required to sign an affidavit indicating their intention to comply with the immunization requirements within 30 days of the child’s arrival in the United States. The vaccination affidavit can be found at https://eforms.state.gov/Forms/ds1981.pdf.
Most children throughout the developing world receive BCG, hepatitis B, polio, measles, diphtheria, tetanus, and pertussis vaccines. Upon arrival in the United States, >90% of newly arrived internationally adopted children need catch-up immunizations to meet ACIP guidelines since rotavirus, Haemophilus influenzae type b (Hib), pneumococcal conjugate, hepatitis A, mumps, rubella, varicella, meningococcal, and human papillomavirus vaccines are often not available or given in these countries. Reliability of vaccine records appears to differ by, and even within, country of origin. Some children may have an immunization record with documentation of the vaccines and dates they were given, and others may have incomplete documentation or no records at all. MMR is not given in most countries of origin, as measles vaccine is often administered as a single antigen. In addition, some children may be immune to hepatitis A, measles, mumps, rubella, or varicella as a result of natural infection. A clinical diagnosis of any of these diseases, however, should not be accepted as evidence of immunity.
Providers can choose 1 of 2 approaches for vaccination of internationally adopted children. The first is to reimmunize regardless of immunization record. The second, applicable to children aged ≥6 months, is to test antibody titers to the vaccines reportedly administered and reimmunize only for those diseases to which the child has no protective titers. Immunity to B. pertussis is an exception; antibody titers do not correlate with immune status to B. pertussis . However, higher protective antibody levels to diphtheria and tetanus might imply protective antibody levels to B. pertussis . Immunity to hepatitis B is also an exception, as anti-HBs as a correlate of vaccine-induced protection has only been determined for people who have completed an approved vaccination series.
For children ≥6 months of age, testing can be done for diphtheria (IgG), tetanus (IgG), hepatitis B (as outlined above), and Hib. For children ≥12 months of age, testing can also be done for measles, mumps, rubella, hepatitis A, and varicella. Since April 2016, a bivalent polio vaccine has been used in many resource-poor countries. Thus, children born on or after this date who do not have documentation of US and WHO age-appropriate inactivated polio vaccine, vaccination should be given a series of IPV vaccine. Reimmunization with pneumococcal vaccine is recommended given that there are 13 serotypes in the vaccine. ACIP recommends that children with positive hepatitis B surface antibody should have documentation of 3 appropriately spaced doses of hepatitis B vaccine to be considered immune. For children with positive hepatitis B surface antibody and positive hepatitis B core antibody, vaccination is not required as they are considered to be immune after natural infection. Passively acquired maternal antibodies to HBV core antigen may be detected in an infant up to age 24 months.
Once the immunization record has been assessed and antibody level results are available, any indicated immunizations should be given according to the current ACIP schedule for catch-up vaccination. If the infant is <6 months old and there is uncertainty regarding immunization status or validity of the immunization record, the child should be immunized according to the ACIP schedule.
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Mary Allen Staat, Simone Wien, Emily Jentes