Peer-reviewed article
Estimating the Risk of Subacute Sclerosing Panencephalitis After Measles in Okinawa, Japan, 1986-2007.
Kobayashi Y, Takahashi T, Hirayasu K, Sunagawa T ·
Summary
Written by AI, not yet AICS's view · claude-haiku-4-5-20251001This study estimated the risk of subacute sclerosing panencephalitis (SSPE), a rare fatal brain disease that develops years after measles infection, in Okinawa, Japan between 1986 and 2007. Researchers identified 17 SSPE cases and used surveillance data to estimate measles cases, finding that SSPE occurred in approximately 1 per 3,944 measles infections overall, but much more frequently in infants under one year old. The findings highlight the long-term dangers of measles, particularly when infection occurs in early childhood, and underscore the importance of maintaining high vaccination coverage.
Key points
- Seventeen SSPE cases were identified with onset during 1994-2009, predominantly in males (71%)
- SSPE risk was estimated at one per 3,944 measles-related outpatient visits (95% CI: 1054-6995)
- Risk was significantly higher in infants under 1 year: one per 910 outpatient visits (95% CI: 416-1403)
- In 1990, during a major outbreak, SSPE risk was one per 1,828 outpatient visits
- Most SSPE cases had documented measles infection in 1990, demonstrating the delayed onset of 4-19 years
Limitations
The study is limited to Okinawa and may not be generalizable to other regions. The estimation of measles-related outpatient visits relies on sentinel surveillance data which may not capture all measles cases, particularly mild cases that did not seek medical attention.
Abstract
Background Subacute sclerosing panencephalitis (SSPE) is a rare, fatal, late complication of measles that develops years after infection, particularly following measles in early childhood. In Japan, measles incidence has declined markedly after improved vaccination coverage and verification elimination; however, recent SSPE epidemiology remains poorly characterized. Methods SSPE cases were identified from the Intractable Disease Treatment Research Project, the Research Project on the Treatment of Children with Specified Chronic Diseases, and Okinawa-specific publications. Measles-related outpatient visits (1986-2007) were estimated by public health center jurisdiction using annual pediatric sentinel surveillance reports and outpatient visit volumes from the Static Survey of Medical Institutions. Ratio estimation with finite population correction was applied. Results Seventeen SSPE cases were identified, 71% in males. SSPE onset occurred during 1994-2009, at a mean age of 8.1 years. The year of measles infection was known for 14 cases, most frequently 1990. For risk estimation, 16 infections occurring during 1986-2007 were included. SSPE risk was estimated as one per 3944 estimated measles-related outpatient visits (95% CI: 1054-6995). In 1990, SSPE risk was one per 1828 outpatient visits (95% CI: 836-2820). Among infants aged < 1 year, SSPE risk was one per 910 outpatient visits (95% CI: 416-1403). Conclusions Estimating denominators for medically attended measles cases from sentinel surveillance enabled quantification of SSPE risk during historical outbreaks in Okinawa. The higher risk during infancy emphasizes the long-term consequences of measles transmission and the need to maintain high measles vaccination coverage.