Twenty-one percent of internationally adopted children demonstrated evidence of latent tuberculosis infection on their first tuberculin skin test, according to results from a single-center study.
And the rate of latent TB infection in those retested at least 3 months after a second tuberculin skin test (TST) was 20%.
The findings underscore the need for internationally adopted children to be tested for TB when they arrive in the United States, according to investigators Dr. Indi Trehan of the department of pediatrics at Cincinnati Children's Hospital Medical Center and his associates.
“TB screening is important, and it should be viewed in the context of postinstitutionalized children,” Dr. Todd J. Ochs, a Chicago-based adoption pediatrician who was not affiliated with the study, said in an interview. “Intestinal parasites, especially Giardia lamblia, potential exposure to HIV, hepatitis B and C, syphilis, malnutrition (kwashiorkor and marasmus), developmental delays, and emotional and psychological problems, all are seen in these children. The mantra when assessing them should be 'remember who I was, not who I am.'”
Dr. Trehan and his associates evaluated 527 children at the University of Cincinnati's International Adoption Center who had an initial TST within 2 months of arriving in the United States (Pediatrics 2008;122:e7-e14 [doi:10.1542/peds. 2007–1338]). A repeat TST at least 3 months after the initial one was recommended for those whose initial test was negative or not read.
The mean age of the children was 23 months and 54% were female. Most were from Russia, China, Guatemala, Ka-zakhstan, and South Korea.
Of the 527 children, 111 (21%) had evidence of latent TB infection after their initial TST.
Of the 416 children with an initially negative TST, only 191 (46%) had a repeat test performed and read at least 3 months after their initial TST, even though the researchers recommended repeat testing to adoptive parents and their primary care physicians. Of these, 38 (20%) had evidence of latent TB infection.
“Presumably, these children were not exposed to TB in the United States but instead, at this later date, were better able to mount an appropriate delayed hypersensitivity response to the TST,” the researchers commented.
“The hypothesis that this is perhaps a result of improved nutrition is supported by our data showing that those with an initially positive TST result had a higher weight-for-age z score (−1.13 vs. −1.38),” they wrote.
Dr. Ochs, who is the father of four internationally adopted daughters and one biological daughter, noted that when most internationally adopted children present to physician offices “it's very rare that there is family history, so we're seeing children who we know nothing about their history, and we're trying to assess their health. They all need infectious diseases screening. They all need eye exams, hearing exams, developmental evaluations. Many of them also need psychological support. We need to be meticulous with these kids.”
He recommends administering a repeat TST 6 months after the initial test in internationally adopted children as well as in foster children, “who may have had multiple placements. They may have entered the health care system because they were being handed off from one caregiver to another and may have been exposed to tuberculosis.”
Children should be considered a high-priority group for treatment of TB not only because of their risk for severe disease and lifetime risk for reactivation of disease, but also because they often serve as index cases for widespread transmission of TB, the investigators commented.