Factors associated with protective antibody levels to vaccine preventable diseases in internationally adopted children.

To determine which factors are predictive of protective antibody against vaccine-preventable diseases in internationally adopted children, we evaluated 562 children with serologic testing for at least one vaccine antigen before receiving a US vaccination. Vaccination status was defined as the number-of-doses recorded and as the presence of an up-to-date and valid record according to the American Academy of Pediatrics and the Advisory Committee on Immunization Practices guidelines. The number-of-doses recorded was the best predictor of protective antibody. These findings suggest that other options for immunization verification guidelines for internationally adopted children should be considered by policy makers.