Molecular surveillance of rubella virus in Beijing, China during 2010–2021: Progress and challenges in rubella elimination

Abstract

Rubella is listed by the World Health Organization (WHO) as a disease that needs to be eliminated worldwide. The aim of this study was to understand the progress and challenges towards rubella elimination in Beijing, China, by analyzing molecular surveillance data combined with immunization and surveillance strategies as well as epidemiological data. With high immunization coverage under the 3-dose policy (8 months, 18 months, and 6 years) and supplementary immunization activities for the floating population, rubella incidence showed a downward trend since 2010, despite two epidemics that occurred in 2014–2015 and 2019. The reported rubella cases were generally concentrated in the age group of 15–34 years. Although citywide surveillance for congenital rubella syndrome (CRS) has been carried out since 2016, only one case has been confirmed by laboratory testing. Furthermore, molecular surveillance data showed that rubella viruses (RVs) circulating in Beijing during 2010–2020 were evidently heterogeneous; the domestic lineage 1E-L1 and multiple imported lineages, including 2B-L1, 1E-L2, and 2B-L2c, were identified in the last decade. Meanwhile, two lineage-related switches were determined, including the displacement of lineage 1E-L1 with lineage 2B-L1 around 2014 and the transition between lineage 2B-L1 and lineage 1E-L2 and 2B-L2c in 2018–2019. This RV transmission pattern was similar to that observed across the country, whereas lineages 1E-L1 and 2B-L2c were prevalent in Beijing for a shorter period. Overall, these results indicate the need to maintain routine immunization with rubella-containing vaccines, promote regular supplementaryimmunizationactivities, and enhance rubella and CRS surveillance even in order to accelerate rubella elimination in Beijing. Further, the existing immunization strategies must be optimized to further close the immunity gap.