Abstract
Introduction
Rubella is a highly contagious viral infection with mild symptoms that primarily affects children and young people. It is caused by the rubella virus, which spreads via respiratory droplets when infected people sneeze or cough. The infection during pregnancy, particularly in the first trimester, causes miscarriage, fetal death, stillbirth, or congenital abnormalities in children, known as congenital rubella syndrome (CRS). Every year, more than 100,000 children are born with CRS worldwide. This study aims to analyze the characteristics of rubella cases in Cambodia from 2015 to 2022 and explore control techniques.
Methods
This study utilized several program data sources to analyze epidemiological trends and provide a comprehensive approach to understanding the impact of vaccination on rubella control from 2015--2022 in Cambodia. These data were collected from national surveillance databases, vaccination data, and data from laboratory surveillance systems. By combining these surveillance data and MR coverage data annually, this study offers insights into the effectiveness of rubella control strategies and identifies areas for future improvement.
Results
Between 2015 and 2022, the National Immunization Program (NIP) reported 9,755 suspected cases of rubella and 130 laboratory-confirmed rubella cases, with an average annual incidence of 1.01 per million people. Rubella cases increased over time, reaching 1.17 per million people in 2015 and 1.87 per million people in 2019, peaking at 2.45 per million people in 2020, and then decreasing. Additionally, the number of reports of suspected cases increased over time, peaked in 2020 (2,857 cases) and then declined. Among the total 9,755 suspected cases, Phnom Penh reported the most cases (23.9%), followed by Kandal province (8.3%) and other provinces. The 9–59-month-old group accounted for 49.2% (64/130) of the rubella cases. Fewer than half (43.0%) of them were boys. In all years, we observed that girls were more likely than boys to contract rubella. The rainy season accounted for 54.6% of all cases, whereas the dry season accounted for 45.4%. Regarding the vaccination status of eligible rubella cases (N=111), 34.2% of cases had two doses or more, 57.7% had one dose, and 8% had not received any dose. Official MR1 coverage was high, more than 95%, and MR2 coverage was less than 90% from 2015 to 2022.
Conclusion
This study highlights that rubella circulated throughout the country and peaked from approximately 2019 to 2020, before decreasing trends in rubella incidence were observed. By maintaining high MR coverage and enhancing regular surveillance, Cambodia can continue to control and eventually eliminate rubella, safeguarding the health of its population, particularly women and children.