January 2001
ATLANTA - New recommendations by the Advisory
Committee on Immunization Practices (ACIP) emphasize repeating the
diphtheria-tetanus-pertussis (DTP) and polio vaccine series in internationally
adopted children. Recommendations were reached amidst two distinct points
regarding antibody measurement.
"Are we looking for protective levels or are we looking for evidence that the child has been immunized?" asked Margaret Rennels, MD, professor, department of pediatrics, University of Maryland School of Medicine in Baltimore.
It's important to distinguish between the two, according to John Modlin, MD, professor of pediatrics, Dartmouth Medical School in Lebanon, N.H. and ACIP chairman.
"We made a decision based on the best information available, and it's a very reasonable and practical decision to encourage reimmunization," said Modlin. "I think the statement will provide some helpful background information to those physicians who need it in unusual situations."
"The bottom line is if you're adopting one of these children, he or she should be seen and evaluated within two weeks of coming to this country," said Carol J. Baker, MD, professor of pediatrics, Baylor College of Medicine in Houston, and a member of the Red Book committee.
"With regard to vaccination, if there's any doubt, a child should be re-immunized to make sure he or she is protected. It's also recommended that blood be taken for testing of hepatitis B and HIV. When [physicians] do the first blood test for hepatitis B (HBV) and HIV, that's when I'd make the decision whether serologies would assist with determining the need for re-immunization."
If any errors are to be made, they should be in the direction of ensuring foreign adoptees are protected against preventable diseases, said Baker.
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Department of State figures show the number of American families adopting children from abroad increased from 8,102 in 1989 to 16,369 in 1999. Approximately 70% come from China, Russia and Eastern Europe, and most live in orphanages before they are adopted.
Margaret Hostetter, MD, professor of pediatrics, Yale University, identified three irregularities on immunization certificates in a post-adoption review of internationally adopted children:
From 1996 to 1998, in a prospective study of 55 children from China, Russia and Eastern Europe, Hostetter found 38% had protective titers against diphtheria and tetanus. From 1998 to 2000, Dana Johnson, MD, and colleagues at the University of Minnesota expanded the study with an additional 56 children from the same countries. Thirty-nine percent were found protected.
"From our data in 111 children, we'd say that two-thirds of children from these countries appear not to be protected against diphtheria and tetanus," said Hostetter.
A Minnesota group looked at an additional 45 children adopted from India, Philippines, Guatemala, Korea, Vietnam and other countries between 1998 and 2000. They found 51% had protective titers against both diphtheria and tetanus.
Overall, of the 156 total children studied, protective titers against diphtheria and tetanus were present in 42%.
Mary Staat, MD, MPH, professor of pediatrics, University of Cincinnati, and of Cincinnati Children's Hospital Medical Center, examined antibody levels to diphtheria and tetanus in more than 50 children who had written documentation of two or more DTP vaccines.
As in Hostetter's study, most children came from China, the former Soviet Union, Eastern Europe and several Asian countries. However, Staat's numbers differed substantially from Hostetter's because of the testing methods employed. Staat used an ELISA test in her study, and Hostetter used hemagglutination inhibition testing.
According to Modlin, Hostetter was testing to see if the study population was immunized. "As such, the methods she used were quite appropriate and probably quite accurate," he noted. "But (Hostetter's) tests may not be the most accurate test to determine immunity."
Seventy-eight percent of Staat's study patients had received all their vaccine dosages while living in an orphanage. Overall, 100% had serological evidence of protection against diphtheria (ELISA > 0.01 IU/ml) and 84% had protection against tetanus (ELISA > 0.5 IU/ml).
In Staat's study, all except for one of the foreign adoptees without protective tetanus antitoxin levels had records showing they received at least three doses of vaccine.
Staat also measured protection against HBV in 36 children from the same regions who had records showing they received two or more doses of a hepatitis B vaccine (Hep B) and had no evidence of chronic infection. Sixty-seven percent of those patients had protective anti-Hep B levels.
According to a document released recently at the ACIP meeting, general recommendations made in 1994 state "the acceptability of vaccinations received outside the United States depends primarily on whether receipt of the vaccine was adequately documented and whether the immunization schedule (ie, age at vaccination and spacing of vaccine doses) was comparable with that recommended in the United States. Any dose (with written documentation) administered at the recommended minimum intervals (and ages) can be considered valid."
Baker said updates to the ACIP recommendations are compatible with and expand upon information provided in the 2000 Red Book which states "Immunization records for international adoptees from some areas (eg, Eastern Europe, Russia and China), especially children from an orphanage, may not accurately reflect protection because of inaccurate or unreliable records, lack of vaccine potency or other problems."
Evaluation of antibody titers may be reasonable for these children, and if there is any question of whether immunizations were administered or immunogenic, the best course is to repeat them, according to the Red Book.
The next edition of the Red Book will most likely contain updated information on vaccination of foreign adoptees, especially as more study data become available, said Baker.
While Staat agrees with ensuring protection in these children, she said one should use good tests to check antibody levels. "We have kids that are 5 or 6 years of age and we could potentially give them 12 to 15 extra shots that they wouldn't need," said Staat.
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