KEYWORDS:
Measles Outbreak, Imported Measles, Epidemiological Investigation, Registry

BACKGROUND:
In April 2002, the New York City Department of Health and Mental Hygiene was notified of a confirmed case of imported measles in a Pakistani-American infant. Outbreak investigation included identification of all exposed individuals and determination of their measles immune status. The Citywide Immunization Registry (CIR) was recruited to assist in the investigation by identifying the exposed individuals who had a documented prior dose of a measles-containing vaccine (MCV).

OBJECTIVE:
To describe the role of an immunization registry in facilitating an epidemiological investigation of a measles outbreak.

METHOD:
A total of 64 children were identified as being exposed to the index case; 63 were under age 14 and were searched for in the CIR to determine their vaccination status. Children 5 years and younger and children without a CIR-documented MCV were contacted first.

RESULT:
Of the 16 children that were < 5 years, 10 had a documented MCV listed in the CIR. Of the 23 children that were > 5 years, 11 had received at least one MCV according to the CIR. Twenty-five of the exposed children were < 1 year and not eligible for an MCV, however 11 of them were found in the CIR. Contact investigation was initially targeted to children < 5 years with no CIR-documented MCV, or those who were < 12 months old. Children > 5 years were contacted later because of the MMR (Measles-Mumps-Rubella Vaccine) requirement for school entry.

CONCLUSION:
The CIR helped to target the epidemiological investigation to the two-thirds of children without confirmed vaccination with a MCV.

LEARNING OBJECTIVES:
By eliminating children with confirmed vaccinations and targeting limited resources to those at greater risk, an immunization registry can assist in rapidly limiting the extent of an outbreak.