Internationally Adopted Children: Can Vaccine Records Be Trusted?
Internationally Adopted Children: Can Vaccine Records Be Trusted?
Verla-Tebit E, Zhu X, Holsinger E, Mandalakas AM
Arch Pediatr Adolesc Med. 2009;163:473-479
Previous studies have demonstrated that children adopted from outside of the United States are more likely to require immunization than are American children of the same age. The "Red Book" published by the Committee on Infectious Diseases of the American Academy of Pediatrics recommends that written documentation of immunization be accepted as adequate proof of immunization as long as the dates and antigens are listed. Several issues, however, contribute to the possibility that written documentation may not represent actual immunity in foreign-born adoptees. For example, poor vaccine response in poorly nourished adoptees and differences in the potency of the vaccines used in certain countries may affect immune status.
This study by Verla-Tebit and colleagues was a cross-sectional assessment of how well written vaccination records of children adopted internationally correlate with actual immunity. The subjects were recruited from a single international adoption clinic at a Midwestern medical center from 2001 to 2006. Children with known infections such as hepatitis or HIV were excluded, and data were not included in antigen-specific analyses for any child who had received that particular vaccine in the United States since adoption. All subjects were seen within their first 180 days in the United States.
Children were grouped by preadoption living conditions: exclusively community, exclusively institutional, or combined. The authors obtained serum to evaluate for antibodies to polio 1,2,3, hepatitis B, measles, diphtheria, and tetanus. The authors used nutritional status at presentation to the adoption clinic as a control factor. The authors were able to evaluate data on 465 subjects, and 397 (85.4%) had some vaccination record.
The mean age of the subjects at adoption was 19.4 months, and almost two thirds of the sample were girls. Russia was the country of origin for 41.7% of the subjects, China 20.9%, and Guatemala 15.7%. Notable percentages of the children suffered from "moderate-to-severe" acute malnutrition (5.5%) or chronic malnutrition (15.4%). Just over half of the children (52%) had been cared for in exclusively institutional settings, with 14% cared for exclusively in the community. Twenty-one percent of the children had been "revaccinated" after arrival in the United States and were therefore excluded from vaccine analyses.
When children had the minimum number of recommended vaccines (eg, 1 for measles, at least 3 for diphtheria), the rates of protective immunity were greater than 80% except for polio types 1 and 3. The setting in which children were cared for prior to adoption was not related to immunity except for tetanus, for which it was associated with increased titers. Nutritional status, as measured by growth parameters at first US evolution, was not associated with immunity.
Children adopted from Russia were more likely to be immune to various vaccines. Children adopted from China were less likely to be immune to several vaccines, especially compared with children from Russia.
The authors concluded that written documentation of immunization of international adoptees does not provide adequate proof of immunity.
The authors note that immunity data in US children demonstrate serologic immunity rates of greater than 98% for most vaccines after the same minimal number of doses. Current recommendations are to either screen for immunity or repeat vaccination in all children adopted internationally. These data support that recommendation. For more information on how to approach vaccine-related immunity in children adopted internationally, see pages 35-37 of the CDC's "General Recommendations on Immunization Recommendations of the Advisory Committee on Immunization Practices (ACIP)."
Abstract
Predictive Value of Immunization Records and Risk Factors for Immunization Failure in Internationally Adopted Children
Verla-Tebit E, Zhu X, Holsinger E, Mandalakas AM
Arch Pediatr Adolesc Med. 2009;163:473-479
Summary
Previous studies have demonstrated that children adopted from outside of the United States are more likely to require immunization than are American children of the same age. The "Red Book" published by the Committee on Infectious Diseases of the American Academy of Pediatrics recommends that written documentation of immunization be accepted as adequate proof of immunization as long as the dates and antigens are listed. Several issues, however, contribute to the possibility that written documentation may not represent actual immunity in foreign-born adoptees. For example, poor vaccine response in poorly nourished adoptees and differences in the potency of the vaccines used in certain countries may affect immune status.
This study by Verla-Tebit and colleagues was a cross-sectional assessment of how well written vaccination records of children adopted internationally correlate with actual immunity. The subjects were recruited from a single international adoption clinic at a Midwestern medical center from 2001 to 2006. Children with known infections such as hepatitis or HIV were excluded, and data were not included in antigen-specific analyses for any child who had received that particular vaccine in the United States since adoption. All subjects were seen within their first 180 days in the United States.
Children were grouped by preadoption living conditions: exclusively community, exclusively institutional, or combined. The authors obtained serum to evaluate for antibodies to polio 1,2,3, hepatitis B, measles, diphtheria, and tetanus. The authors used nutritional status at presentation to the adoption clinic as a control factor. The authors were able to evaluate data on 465 subjects, and 397 (85.4%) had some vaccination record.
The mean age of the subjects at adoption was 19.4 months, and almost two thirds of the sample were girls. Russia was the country of origin for 41.7% of the subjects, China 20.9%, and Guatemala 15.7%. Notable percentages of the children suffered from "moderate-to-severe" acute malnutrition (5.5%) or chronic malnutrition (15.4%). Just over half of the children (52%) had been cared for in exclusively institutional settings, with 14% cared for exclusively in the community. Twenty-one percent of the children had been "revaccinated" after arrival in the United States and were therefore excluded from vaccine analyses.
When children had the minimum number of recommended vaccines (eg, 1 for measles, at least 3 for diphtheria), the rates of protective immunity were greater than 80% except for polio types 1 and 3. The setting in which children were cared for prior to adoption was not related to immunity except for tetanus, for which it was associated with increased titers. Nutritional status, as measured by growth parameters at first US evolution, was not associated with immunity.
Children adopted from Russia were more likely to be immune to various vaccines. Children adopted from China were less likely to be immune to several vaccines, especially compared with children from Russia.
The authors concluded that written documentation of immunization of international adoptees does not provide adequate proof of immunity.
Viewpoint
The authors note that immunity data in US children demonstrate serologic immunity rates of greater than 98% for most vaccines after the same minimal number of doses. Current recommendations are to either screen for immunity or repeat vaccination in all children adopted internationally. These data support that recommendation. For more information on how to approach vaccine-related immunity in children adopted internationally, see pages 35-37 of the CDC's "General Recommendations on Immunization Recommendations of the Advisory Committee on Immunization Practices (ACIP)."
Abstract
