TB and Adoption: What Parents Needs to Know
by Deborah Borchers, M.D.
Q: Should my child be tested for tuberculosis? Will she test positive whether or not she has TB, since she has had the TB vaccine?
A: Although many of us think of tuberculosis as a disease of the past, it is still very much with us. Children in the U.S. living in dense urban areas, or those living in proximity to prisoners and homeless persons, may be exposed to TB. TB is widespread in Eastern Europe, Asia, Latin America, and Africa. Orphanage workers may have active infections, and may spread it to the children in their care through coughing and sneezing. According to Dana Johnson, M.D., of the University of Minnesota's International Adoption Clinic, tuberculosis is the most common infectious disease in international adoption, afflicting over 20% of children in certain countries.
Although TB is a chronic infection that can cause permanent damage in almost any part of the body, most children infected with the TB bacteria do not develop the active disease immediately. Instead, in most cases, the body's immune system attacks the bacteria in the lungs and prevents the development of active TB. While an infected child may appear completely healthy (and is not contagious), the TB infection may remain dormant. Without treatment to eradicate it from the body, TB can be reactivated at any time.
In contrast to those with the dormant infection, children with active TB experience fever, fatigue, a persistent cough, weight loss, and poor growth, and can become critically ill. They can also spread TB to others. Active TB can be successfully treated, usually with a combination of drugs, but it is far easier to treat TB before the active disease develops.
Who should be tested?Until fairly recently, medical officials recommended routine TB testing for all children, and TB screening was mandatory for school attendance. These days, however, testing is advised only for children at risk of exposure, i.e., those who have lived in orphanages or other institutions, been homeless, lived in foster care, or emigrated from countries where TB is widespread. Children should be screened shortly after arrival into the family as part of a comprehensive health evaluation, and screened again six months later (to rule out exposure just before the child came to the new family, which might not have triggered a positive result in the first test). Adoptive parents and adoption agency workers should be tested six months after they travel to an at-risk country. In addition, children in the U.S. who are at high risk of exposure should be routinely screened for TB throughout childhood.
The recommended screening for tuberculosis exposure is a skin test known as the PPD (purified protein derivative). The familiar TB tine test (with four dots injected into the arm) is no longer considered reliable. In the PPD test, a tiny, inactive part of the tuberculosis bacterium is injected under the skin in the forearm, resulting in swelling and firmness. For a child in foster care or one who was born abroad, a measurement of 10 millimeters (mm) is considered a sign of tuberculosis exposure and called a "positive PPD," regardless of whether or not he was previously vaccinated for TB. To obtain accurate results, it's important that a health care professional check the tested skin area 48 to 72 hours after the PPD injection.
If your child's PPD test is positive, i.e., greater than 10 mm, the next step is a chest x-ray to rule out active tuberculosis in the lungs. If the chest x-ray shows abnormalities, additional tests are required. Even if there's no evidence of active disease in the lungs, children with positive PPD results should begin treatment with isoniazid, an antibiotic taken daily for nine months. Isoniazid prevents the TB germ, dormant in the body but not yet causing active disease, from becoming active. It's important to continue treatment for the entire nine months to eradicate all TB bacteria. Bacteria that remain in the body when treatment is stopped prematurely can become resistant to standard drugs and are harder to treat.
Although isoniazid can cause liver problems in adults, it is considered safe in healthy children. Isoniazid may interact with other medications, so it's important to tell your doctor about any prescription and over-the-counter drugs, including herbal remedies, that your child is taking. A child with a positive PPD test and a negative chest x-ray is not contagious to others, and can continue to attend school or day care.
Testing and the TB vaccineBecause TB is a significant problem throughout the world, many children receive the BCG (bacille Calmette-Guerin) vaccine. The BCG vaccine, rarely used in the U.S., is usually injected into the shoulder, resulting in a scar similar to that of the smallpox vaccine. Although vaccination helps prevent the TB bacteria from spreading to other parts of the body and helps to protect babies, who are at high risk for serious complications of TB, it doesn't provide long-term protection. Children who receive the vaccination can still become infected.
There is considerable misinformation among adoptive parents and medical professionals as to whether children who have received the BCG vaccine prior to arriving in the U.S. may be accurately tested for exposure to TB. According to recent studies, although a child who has received the BCG vaccine may show a reaction to the PPD test, the PPD test will result in less swelling (under 10 mm) than in a child who has been exposed to the actual disease. In this case—a child with a prior BCG vaccine and a response to PPD but swelling of less than 10 mm—the result is not considered positive for TB. However, a PPD test that causes 10 mm or more of swelling is considered an accurate indication of TB infection, whether or not the child received the BCG vaccine, and the child should have a chest x-ray and begin antibiotic treatment.
TB infection can be a serious health risk if it remains undetected. For more information about TB testing, refer your child's physician to the Red Book, published by the American Academy of Pediatrics Committee on Infectious Diseases. This book, updated every three years, includes the latest recommendations for the evaluation and treatment of tuberculosis, as well as the testing of children previously vaccinated for TB.
Deborah Borchers, M.D., is a founding member of the American Academy of Pediatrics Section on Adoption and Foster Care, and the mother of three children adopted internationally.
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