Thursday 30th of March 2017

Tuberculosis Testing and the BCG Vaccine

In many developing nations, tuberculosis is rampant. Caretakers in orphanages are often actively infected with this germ, spreading it to children through coughing and poor sanitary conditions. Due to the limitations of the health care systems in developing nations, most adults are not treated, and thus children that are exposed may become easily infected.

Because this is such a problem in many countries, institutionalized children are frequently given a vaccine against tuberculosis called the BCG. This vaccine, usually given into the shoulder soft tissue shortly after birth or upon arrival in an orphanage, leaves a scar similar to that from the smallpox vaccine (which is no longer given to children in this country). Frequently the active sore created by the vaccine heals easily, but it may fester and create an open sore that may take considerable time to heal. The BCG vaccine does not protect completely against pulmonary tuberculosis (tuberculosis in the lungs). Instead, it protects children from the complications of tuberculosis, which include spread to the kidneys and spinal fluid surrounding the brain. Given that institutionalized children have a weakened immune system due to malnutrition, this protection, although limited, may be of benefit to these children.

In the United States health care providers use a simple skin test called the PPD (purified protein derivative) to test for exposure to tuberculosis (physicians should no longer be doing the old TB tine test due to its poor reliability). The PPD test is done by injecting a miniscule amount of the tuberculosis germ under the skin and seeing if there is resulting induration, or swelling and firmness, of the skin. The test is interpreted by measuring the amount of this induration. For a child or adult born in a developing nation, a measurement of 10 millimeters (mm) is considered to be the sign of a significant, or positive exposure to tuberculosis. The child should then have a chest x- ray to rule out pulmonary tuberculosis. If the physician finds no evidence of active disease, children should then be started on a medication called Isoniazid, which needs to be taken daily for the next nine months. This prevents the tuberculosis germ, already in the body (but not yet causing disease) from becoming active and resulting in serious illness. Isoniazid sometimes causes liver toxicity in adults, but is considered to be a very safe medication in children. It is important that the treatment with Isoniazid not be interrupted for the whole nine months, as this could result in the germ becoming resistant to the antibiotic. Physicians may need to be reminded that Isoniazid may interact with other medications. Children with a positive PPD test and negative chest x- ray have only been exposed to the tuberculosis germ, and are not contagious to other children or adults in the same way that infected adults are contagious (so they do not need to be excluded from day care or school).

In adults and children who recently were given the BCG vaccine, the PPD test may be positive due to the vaccine itself, rather than from exposure to the germ. The test should still not measure 10 mm. Thus, many physicians are under the mistaken belief that children adopted internationally and received a BCG vaccine should not have a PPD test after arrival home. This assumption is not true. Many children given a BCG test early in life will STILL show no reactivity to the PPD test given a year or more later. According to the Committee on Infectious Diseases of the American Academy of Pediatrics, ALL CHILDREN ADOPTED INTERNATIONALLY MUST HAVE A PPD TEST DONE, REGARDLESS OF WHETHER OR NOT THE CHILDREN HAD A BCG VACCINE. Adoption experts differ on the timing of the PPD test with respect to the BCG vaccine. The test can be done on infants as young as 4 to 6 months, particularly if there is a known exposure. If a child has an actively healing BCG scar at the time of arrival, the PPD should be held until a year after arrival. If a well healed BCG scar is noted but there is no immunization record, the PPD should be done immediately. It is very important that all PPD tests be examined 48 to 72 hours after the test is done by a qualified health care professional, as this test is easily misinterpreted. If a physician does not want to do a PPD test immediately after arrival for whatever reason, then a chest x-ray should be done to rule out active pulmonary tuberculosis.

All children adopted internationally are at high risk for tuberculosis, as well as other diseases not commonly seen in our country. An untreated exposure to tuberculosis could later result in a spread of this germ to the kidneys and brain, resulting in unnecessary illness and possibly even death. Appropriate screening for tuberculosis with treatment with Isoniazid, if necessary, should eliminate the chance of the spread of this deadly germ throughout a child's body, with symptoms only when it is too late.

Just because a child "looks good" in his/her middle class garb with concerned and loving parents does not guarantee that the child is "healthy", without evidence of tuberculosis or other diseases. All children adopted internationally should have screening tests done to evaluate for other diseases which may have no symptoms for many years, but may have long range consequences for a child and his/her family.

Currently recommended screening tests include (but are not necessarily limited to):

  • Hepatitis B surface antigen, surface antibody, core antibody
  • Hepatitis C antibody
  • HIV test
  • Blood test for syphilis
  • Complete blood count, with a hemoglobin electrophoresis if the child is anemic
  • Lead screen
  • Urinalysis to check for kidney problems
  • Stool culture
  • Stool for parasite infections (three specimens are recommended)
  • Thyroid test to rule out low thyroid levels
  • PPD for tuberculosis

In addition, children should have a developmental evaluation and a good examination of their eyes and ears to check for diseases of those systems.

All pediatrician members of the American Academy of Pediatrics should have a book on their shelves, the Red Book, which is the report of the Committee on Infectious Diseases. This book includes the latest recommendations on tuberculosis and the BCG, as well as an entire chapter on the medical evaluation of children adopted internationally. There are a number of adoption medical specialists throughout the country who are available for consultation regarding the varied and complicated health concerns seen in children born in developing nations. All are happy to be of assistance to parents and physicians regarding health concerns in these children. Many pediatricians see only a limited number of children adopted internationally in their practice, and may be unaware of the health risks in these children. Just because a child "looks healthy" does not mean that there are not significant disease exposures. For the sake of a child's future health, it is important to have a complete health screening and evaluation soon after arrival home.

Deborah Borchers, M.D.

Revised May 8, 2000.

Dr. Borchers is a general pediatrician and adoption medicine specialist at the Eastgate Pediatric Center in Cincinnati, Ohio (513/753-2820). Permission to reprint this article is not necessary for parents, social workers or physicians.

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