Measles Outbreak Associated with International Adoption
Abstracts & Commentary
Synopsis: Fourteen cases of measles occurred among children adopted from China, their family members, and a caretaker during February-March 2001. Internationally adopted children may not be adequately immunized against measles and other routine childhood diseases. It is crucial to review the immunization status of international adoptees and to update their vaccinations as soon as possible after arrival in the United States. It is also crucial to assess the routine immunizations of adoptive families and caretakers and to also vaccinate them appropriately.
Sources: CDC. Measles outbreak among internationally adopted children arriving in the United States, February-March 2001. MMWR Morb Mortal Wkly Rep. 2002;51(49):1115-1116; CDC. Accelerated measles control—Cambodia, 1999-2002. MMWR Morb Mortal Wkly Rep. 2003;52(1):4-6.
A 10-month-old child, newly adopted from China, traveled home in February 2001 to Texas via commercial flights. The child had a prodromal fever during the trip, and subsequently developed symptoms consistent with measles including conjunctivitis, coryza, Koplik spots, and a maculopapular rash). Serological testing confirmed measles. The Texas Department of Health and CDC were notified and investigated potential contacts that may have occurred in the adoptive families, the orphanage, US Consulate, local medical facility in China, personnel from the international adoption agencies, and passengers and crew of the flights.
This investigation identified 14 cases of measles in the United States that occurred among recent adoptees from China and their close contacts:
- Ten adoptees—9-12 months old in 7 states (New York, 3; Ohio, 2; Illinois, 1; Indiana, 1; Minnesota, 1; Missouri, 1; Texas, 1);
- Two US-born adoptive mothers (Indiana, 46 years old; Missouri, 39 years old);
- 1 US-born caretaker (Connecticut, 47 years old, lived for 1 week in the household of an adopted child with measles);
- One sibling (Georgia, 28 months old) of a healthy child adopted from China.
All 14 cases of measles occurred during February and March 2001. Thirteen cases were imported. The caretaker was a case of secondary transmission. The timing of illness correlated with measles exposure in China, at the orphanage, during medical screening, or travel. Investigation identified suspected measles cases that occurred prior to the index patient’s illness, and found that children at the particular orphanage had not been immunized appropriately against measles.
The next report, on Cambodia, noted promising results for measles control. Only 34% of the population was immunized against measles in 1990. The vaccine coverage increased to 75% in 1995, but decreased to 63% in 1998-1999. At that point, the measles control program was initiated. Measles incidence has been declining steadily since 2002. Nevertheless, 94-99% of reported measles cases occurred in children younger than 15 years old.
Comment by Lin H. Chen, MD
In the editorial note for the first report, a Table lists measles cases associated with travel or immigration that occurred in the United States from 1997 to 2001. The imported cases account for up to 47% of reported cases of measles annually. The editorial reviews the criteria for immunity to measles in US residents, which include birth before 1957, a history of physician-diagnosed measles, documentation of 2 doses of measles-containing vaccine, or positive measles serology. According to these criteria, the 46-year-old adoptive mother and the 47-year-old caretaker would have been assumed to be immune to measles by having been born before 1957. The outbreak demonstrates that birth before 1957 does not guarantee immunity against measles.
This outbreak highlights 2 aspects of medical evaluation in international adoption: 1) the uncertainty in the immunization status of international adoptees can lead to infection with common childhood diseases and spread of infections; 2) the adoptive families and caretakers may not be fully immunized against common childhood diseases, and can become infected in their travel or contact with internationally adopted children.
In spite of the decreasing incidence in measles and improving vaccine coverage in Cambodia, only 27% of children younger than the age 10 had a history of measles vaccination in 2002. Therefore, children being adopted remain in the group at risk for contracting measles.
What can travel medicine specialists do to prevent measles in families planning to travel for adoption? 1) Ascertain measles immunity of adoptive families, and offer immunization where immunity may be lacking; 2) Recommend evaluation for other caretakers who will have close contact with international adoptees; and 3) Discuss the uncertainty of medical records from the adoptee’s country of origin, and advise evaluation of the internationally adopted child to be done soon after arrival in the United States. Measles is only one of many common childhood diseases that can be associated with international adoption. This outbreak underscores the importance of reviewing routine immunizations as part of the pretravel consultation.
Fourteen cases of measles occurred among children adopted from China, their family members, and a caretaker during February-March 2001. Internationally adopted children may not be adequately immunized against measles and other routine childhood diseases.
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