Infections in International Adoptees
Abstract and Commentary
By Lin H. Chen, MD
Assistant Clinical Professor, Harvard Medical School, Director, Travel Resource Center, Mount Auburn Hospital, Cambridge, MA
Dr. Chen reports no consultant, stockholder, speaker’s bureau, research, or other financial relationship with companies having ties to this field of study.
Synopsis: A review of infectious diseases in internationally adopted children shows low risk of serious infections, but preadoption medical records are unreliable. An increasing number of international adoptees appear to be receiving hepatitis B immunization in their countries of origin, and serological testing for varicella-zoster virus antibodies may be a useful screening strategy in children >1 year old.
Source: Murray TS, et al. Epidemiology and Management of Infectious Diseases in International Adoptees. Clin Microbiol Rev. 2005;18:510-520.
This detailed review examined the epidemiology of infectious diseases in international adoptees, based on previously published series. Specifically, Murray and colleagues summarized data on HIV, hepatitis B, hepatitis C, measles, Mycobacterium tuberculosis, syphilis, Helicobacter pylori, bacterial gastroenteritis, intestinal parasites, scabies, and lice (see Table 1).
Murray et al also studied 105 children consecutively evaluated at their institution, the Yale International Adoption Clinic, from September 2003 to March 2005. Results were similar to those from other series of international adoptees. The risk of infection with HIV, hepatitis B virus, and hepatitis C virus has been low in recent adoptees. Serology showed past varicella-zoster virus (VZV) infection in 25% that correlated with older age (mean age, 57 months). Giardiasis was detected in 20% and scabies in 10%. Hepatitis B virus surface antibody determinations were positive in 70% of adoptees, consistent with past immunization. One of 100 children tested had chronic hepatitis B virus infection. Three of 98 (3.1%) children were found to have congenital syphilis, and had arrived from Russia, Guatemala, and Georgia; 2 of the children with congenital syphilis had no mention of the diagnosis made in their preadoption record.
Murray et al discussed the preadoption medical records, which have been documented to be misleading in previous studies and discordant with the postadoptive medical exam. Postadoption medical screening is important and reliable for identification of infectious diseases of concern. Murray et al described their approaches to screening, which are consistent with the American Academy of Pediatrics guidelines. The routine screening tests include hepatitis B surface antigen, surface antibody, and core antibody, hepatitis C antibody, varicella-zoster antibody, urinalysis, VDRL and FTA, PPD skin test for M. tuberculosis, complete blood count with differential, serum lead level, thyroid stimulating hormone level, stool test for ova and parasites, stool Giardia antigen, and HIV status. For HIV, the children are first tested for both HIV-1 and -2 by serum ELISA, with confirmatory Western blot for any positive ELISA test. Murray et al also test with a PCR assay for circulating HIV in recent arrivals.
Finally, Murray et al recommended full repeat immunization for international adoptees under 1 year of age. Vaccines for varicella-zoster virus, H. influenzae b, and Streptococcus pneumoniae are generally not given in most countries of origin of international adoptees. Murray et al usually immunized all international adoptees with these vaccines except for VZV, for which they routinely assessed the antibodies in children over 1 year of age because of the frequency of positive titors.
Commentary
International adoption continues to grow in popularity in developed countries. In the United States, the number of international adoptees increased from 7093 in 1990 to 22,884 in 2004.1 Since the initial study on health status of internationally adopted children was published by Hostetter and colleagues, studies conducted by others have also assessed infectious disease incidence in this unique group of immigrant children, as well as in recent reviews.2-10 These studies have illustrated risks of infection with hepatitis B virus, gastrointestinal parasites, bacterial enteric pathogens, tuberculosis, hepatitis A virus, hepatitis C virus, HIV, syphilis, cytomegalovirus, scabies, and lice (see Table 1).
Data from the Yale International Adoption Clinic (YIAC) add support to previously demonstrated risks, although the series is small. It is reassuring to learn that while giardiasis and scabies have remained significant, serious infections such as HIV, hepatitis B virus, and hepatitis C virus have occurred infrequently in recent adoptees. It is possible that preadoption screening has removed children with serious infectious diseases from the adoption process. For example, while the previous series have reported chronic hepatitis B infection in 2-6% of international adoptees (and up to 20% in children adopted from Romania),2-9 the Yale group found only 1% of adoptees with HBsAg. The Yale group did not specifically state their findings on HIV and hepatitis C virus infections, but implied that infection rates were low.
Another reassuring finding at YIAC is their high seropositivity of hepatitis B surface antibody (70%) without evidence of past infection, indicating immunity derived from hepatitis B immunization. Together with the chronic hepatitis B virus infection of 1%, these data suggest a declining risk of hepatitis B infection, compared to prior series on internationally adopted children.
The YIAC has found a 25% seroprevalence rate for VZV, which increased with age. The seropositive children were usually > 1 year old, and serotesting for VZV in international adoptees appears reasonable for this age group. Cost-effectiveness of serotesting for varicella immunity has been done in refugee children but not in international adoptees.11
The YIAC data on congenital syphilis is less reassuring, with 3.1% being positive. The children were from Russia, Guatemala, and Georgia. This may reflect an increase in the incidence of syphilis in the former Soviet Republic, and international adoptees should be screened carefully. Two of the children with congenital syphilis were not reported to have the diagnosis in the preadoption medical records, highlighting the importance of the postadoption medical screening.
The stool giardia antigen was positive in 27%, 50%,and 75% of children from Russia, Belarus, and Ukraine, respectively (see following article). The infection appears to have remained highly prevalent in children from the former Soviet Republic. Although the Yale group did not describe the prevalence of other gastrointestinal parasites in their clinic, previous reports on international adoptees have found a number of parasitic infections. Pathogenic infections that have been identified through screening include Cryptosporidium spp, Trichuris trichiura, Ascaris lumbricoides, Strongyloides stercoralis, and Dientamoeba fragilis, and these warrant treatment.12
Many families planning international adoption consult travel medicine specialists prior to their travel to meet their children. The adoptive parents are usually concerned about the health status of the, as yet, unfamiliar child. Information regarding the risk of infectious diseases in internationally adopted children helps families prepare for proper screening and care of their adopted children. Such information is the basis on which pre-travel recommendations for families planning international adoption are formulated, and may evolve over time.13
References
- US State Department. Immigrant visas issued to orphans coming to the United States. Available at www.travel.state.gov Accessed August 20, 2005.
- Hostetter MK, et al. Medical Evaluation of Internationally Adopted Children. N Engl J Med. 1991;325:479-485.
- Jenista JA. Preadoption Review of Medical Records. Pediatr Ann. 2000;29:212-215.
- Miller LC. Caring for Internationally Adopted Children. N Engl J Med. 1999;341:1539-1540.
- Staat MA. Infectious Disease Issues in Internationally Adopted Children. Pediatr Infect Dis J. 2002;21:257-258.
- Johnson DE, et al. The Health of Children Adopted from Romania. JAMA. 1992;268:3446-3451.
- Albers LH, et al. Health of Children Adopted from the Former Soviet Union and Eastern Europe. Comparison with Preadoptive Medical Records. JAMA. 1997;278:922-924.
- Miller LC, et al. Health of Children Adopted from China. Pediatrics. 2000;105: e76. Accessed August 20, 2005.
- Saiman L, et al. Prevalence of Infectious Diseases Among Internationally Adopted Children. Pediatrics. 2001;108:608-612.
- Miller LC. International Adoption: Infectious Diseases Issues. Clin Infect Dis. 2005;40:286-293.
- Figueira M, et al. Cost-Effectiveness of Serotesting Compared with Universal Immunization for Varicella in Refugee Children from Six Geographic Regions. J Travel Med. 2003;10:203-207.
- Wolfe MS. Intestinal Parasites in International Adoptees. Clin Infect Dis. 2005;41:122.
- Chen LH, et al. Preventing Infectious Diseases During and After International Adoption. Ann Intern Med. 2003;139:371-378.
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