Objectives
Subacute sclerosing panencephalitis (SSPE) is a rare but fatal neurodegenerative disease caused by persistent measles virus infection. After a significant measles outbreak in 2000–2001, the Republic of Korea implemented a nationwide measles elimination program, which led to a dramatic reduction in measles incidence. This study aimed to evaluate the impact of these measles elimination efforts on the incidence of SSPE in the Republic of Korea.
Methods
This nationwide, population-based retrospective cohort study identified patients newly diagnosed with measles and SSPE between 2007 and 2022, registered in the Health Insurance Review and Assessment Service (HIRA) and Korea Disease Control and Prevention Agency (KDCA) databases. Population-based incidence rates of measles and SSPE were calculated and compared annually.
Results
A total of 236 measles cases (HIRA data) and 1,168 measles cases (KDCA data), along with 2,736 SSPE cases, were diagnosed during the study period. Measles incidence significantly declined, reaching zero cases in 2021, while SSPE incidence displayed an upward trend, peaking in 2014. The mean age at SSPE onset was 21.2 years, with a marked male-to-female ratio of 13.0:1.
Conclusion
SSPE incidence was remarkably low in the post-outbreak period, likely attributable to successful measles control. This study underscores the critical importance of maintaining low measles incidence through sustained vaccination efforts, preventing SSPE and other measles-related complications.

Objectives
Despite effective vaccination strategies, measles remains a global public health challenge. The study explored individual and contextual factors associated with measles infection in Malaysia from 2018 to 2022, informing the development of targeted public health interventions. Methods: This cross-sectional study utilised data from the Ministry of Health, the Department of Statistics, and the Department of Environment Malaysia. Multilevel logistic regression analysis was employed to examine individual-level factors, including age, sex, ethnicity, nationality, contact history, travel history, and vaccination status. Concurrently, contextual factors were assessed, encompassing district-level determinants such as population density, median household income, urbanisation, the number of health and rural clinics, vaccination rates, fine particulate matter less than 2.5 μm (PM2.5) levels, relative humidity, and temperature, to determine their impact on measles infection risk. Results: Measles infection was significantly associated with various individual factors. These included age (adjusted odds ratio [aOR], 1.02; 95% confidence interval [CI], 1.02–1.03), ethnicity, non-Malaysian nationality (aOR, 34.53; 95% CI, 8.42– 141.51), prior contact with a measles case (aOR, 2.36; 95% CI, 2.07–2.69), travel history (aOR, 2.30; 95% CI, 1.13–4.70), and vaccination status (aOR, 0.76; 95% CI, 0.72–0.79). Among contextual factors, urbanisation (aOR, 1.56; 95% CI, 1.16– 2.10) and the number of clinics (aOR, 0.98; 95% CI, 0.97–0.99) were significant determinants. Conclusion: This multilevel logistic regression analysis illuminates the complexities of measles transmission, advocating public health interventions tailored to individual and contextual vulnerabilities. The findings highlight the need for a synergistic approach that combines vaccination campaigns, healthcare accessibility improvements, and socioeconomic interventions to effectively combat measles.