Learning Objectives for this Presentation:
By the end of the presentation participants will be able to judge the impact of measles immunization on the prevention of cases of SSPE.

Background:
The most severe sequella of measles infection is subacute sclerosing panencephalitis (SSPE), a fatal disease of the central nervous system that generally develops 7-10 years following infection. From 1989 to1991, a resurgence of measles occurred in the United States (US) with 55,622 reported measles cases.

Objectives:
The purpose of the study was to identify cases of SSPE that were linked to the resurgence and to calculate the risk of developing SSPE.

Methods:
Brain tissue samples from 11 patients with presumptive diagnosis of SSPE were tested for the presence of measles RNA. Measles genotypes were determined by reverse transcription-polymerase chain reaction (RT-PCR) and analysis of the sequences of the PCR products. A literature search was conducted for case reports of SSPE patients with measles during 1989-1991.

Results:
The measles sequences derived from brain samples of 11 SSPE patients confirmed the diagnosis of SSPE. Five of the 11 SSPE patients tested by RT-PCR and 7 patients identified from published case reports could be linked to measles infection in the US during 1989-1991. The estimated risk of SSPE was 10-fold higher than the previous estimate reported for the US in 1982.

Conclusions:
Measles vaccination prevents more cases of SSPE than originally estimated. Our data support previous epidemiologic and genetic studies that have found no evidence that vaccine virus can cause SSPE.