SAN FRANCISCO — Records for most vaccines from most countries of origin for children adopted internationally are trustworthy, Dr. Bindy Crouch said in a poster presentation at the annual meeting of the Pediatric Academic Societies.
For this reason, Dr. Crouch of the State University of New York at Stony Brook and her colleagues recommend that antibody titers should be tested before revaccinating adopted children who have documentation of vaccines that were given in their countries of origin.
The study involved a retrospective chart review of 219 internationally adopted children seen between January 2003 and December 2004.
Of those children, 72 came from China, 87 from Russia, 28 from Korea, 19 from Guatemala, 4 from Ethiopia, 2 each from Belarus, Colombia, and the Philippines, and 1 each from India, Kazakhstan, and Romania.
At the time of adoption, 73% were under the age of 2 years.
With the exception of hepatitis B among children adopted from Korea and mumps among all children, the percentages of positive antibody titers were similar to rates that have been reported in U.S. vaccine studies.
For example, of the children with records of DTP vaccine, 99% were titer positive for diphtheria antibody and 88% were titer positive for tetanus. Children with records of polio vaccine were 95% titer positive, those with records of measles vaccine were 92% titer positive, and those with reported rubella vaccine were 92% titer positive.
On the other hand, of children adopted from Asian countries other than China (28 of 31 of these children came from Korea), only 63% of those who had records of hepatitis B vaccine were titer positive. This was a significantly lower percentage of positive titers than that seen in children from all other areas.
The investigators suggested that the lower percentage of positive hepatitis B titers in children from Korea may be due to the manufacturing, storage, or administration of vaccine, but it is also plausible that Korean children have poorer responses to the vaccine.
Only 67% of all the adopted children with records of mumps vaccine had positive titers, which the investigators said was significantly lower than the percentage reported in U.S. vaccine studies. Investigators said that this may be attributable to issues with vaccine handling and storage, inaccurate record keeping, or an impaired immune response to the mumps vaccines used.
The meeting was sponsored by the American Pediatric Society, Society for Pediatric Research, Ambulatory Pediatric Association, and American Academy of Pediatrics.