PEDIATRICS Vol. 108 No. 4 October 2001, pp. 1050-1051

Immunization Status of Internationally Adopted Children

To the Editor.

Many internationally adopted children arrive in the United States with incomplete or uncertain vaccination status. Some have suggested that even children who have received adequate numbers of vaccines for tetanus and polio have inadequate titers, resulting from poor immunogenicity of the vaccines, impaired immune responses (possibly attributable to malnutrition), or incorrect records.^1,2 Some physicians recommend revaccinating all international adoptees at arrival in the United States.³ We reviewed the vaccination status and titers of 70 newly arrived internationally adoptees to assess the adequacy of vaccines given in the children's birth countries, and related the results to assessment of their nutritional status at arrival in the United States. We also analyzed whether vaccines administered in the orphanage or community differed in immunogenicity.

The children (41 boys, 29 girls) were from Russia (17), China (13), Romania (9), Lithuania (8), Phillipines (6), Kazakhstan (5), Colombia (3), India (3), Guatemala (2), Lebanon (1), Moldova (1), Latvia (1), and Bulgaria (1). The age at arrival in the United States was 38.2 months ± 24.07 months (range: 9 months to 10 years). Age at evaluation was 42.6 months ± 23.6 months (range: 10 months to 10 years 1 month). Sixty-five percent of children had resided entirely in institutional care before adoption. Nutritional status of the children was similar to other populations of international adoptees. Z scores for height, weight, and head circumference were 1.53 ± 1.34; 1.10 ± 1.20; and 1.10 ± 1.28, respectively. Many children had associated medical problems including parasites (25%), infections (25%), rickets (11%), birth defects (9%), reactive purified protein derivative (9%), severe anemia (5%), hepatitis B or C (5%), elevated lead levels (3.5%), uncertain age (3.5%), and hemophilia (1.7%).

Titers (enzyme-linked immunosorbent assay/neutralizing antibodies) were obtained in children who had received 3 diphtheria, pertussis, and tetanus, or polio vaccines, or vaccination against measles, mumps, or rubella. No child had received vaccines in the United States at the time samples were collected. Percent of children with adequate immunity for each disease is shown:

Tetanus Diphtheria Pertussis Polio-1 Polio-2 Polio-3 Measles Mumps Rubella Immune 61% 88 50 58 65 62 90 66 79 Borderline 33 9 0 0 0 0 0 14 4 Not immune 3 3 50 42 35 38 10 19 16

No relation was found between immunity and the age, nutritional status, or associated medical problems of the child, or the site of vaccine administration (community versus orphanage).

This survey confirms that immune responses to vaccines administered by sending countries to international adoptees are incomplete, and that a significant percentage of children lack adequate immunity despite satisfactory vaccination records. We conclude that international adoptees should be tested for titers to vaccine-preventable diseases to ascertain their immune status on arrival and to guide decisions about revaccination.

Laurie C. Miller, MD
Kathleen Comfort, PT
Natasha Kelly
International Adoption Clinic
Tufts-New England Medical Center
Boston, MA 02111

REFERENCES

1. Hostetter MK, Johnson DJ Immunization status of adoptees from China, Russia, and Eastern Europe [abstract]. Pediatr Res. 1998; 43:147
2. Miller LC Internationally adopted children-immunization status [letter]. Pediatrics. 1999; 103:1078 [Free Full Text]
3. American Academy of Pediatrics. 2000 Red Book: Report of the Committee on Infectious Diseases. Pickering LK, ed. Elk Grove Village, IL: American Academy of Pediatrics; 2000