Unveiling Rubella Antibody Trends of Healthy Populations in Guangzhou and Heyuan, Guangdong Province, China, 2021-2023

Abstract Background Serological surveillance of rubella antibodies is favorable for disease risk assessment and evaluation of vaccination effectiveness, and understanding the immunity status of healthy individuals. Methods From 2021 to 2023, serum samples were collected from healthy residents in Guangzhou and Heyuan of Guangdong Province, China. Rubella IgG antibody levels were determined by enzyme-linked immunosorbent assay (ELISA) and analyzed in combination with vaccination history. Results In this study, a total of 5,092 participants were enrolled, and the positivity rate of rubella IgG antibodies is 84.58% (95% CI: 83.56%-85.56%). The geometric mean concentration (GMC) was 37.45 IU/mL (95% CI: 36.34–38.57). The seropositivity rate and concentration of rubella antibody exhibited a U-shaped curve across age groups. The highest rates were observed in the 8 months − 3 years group (98.21%) and the > 60 years group (92.57%), while the lowest seropositivity rate was found in the 17–25 years group (67.17%). The seropositivity rate in the 2 doses vaccinated group (93.78%) was significantly higher than both the unvaccinated group (82.50%) and the 1 dose vaccinated group (78.67%). Based on the Generalized Additive Model (GAM) prediction, the antibody of 2 doses vaccination group showed an annual decline rate of 5.6%, with predicted persistence for 32.6 years. Conclusions The rubella IgG antibody among healthy populations in Guangdong Province during 2021–2023 remained at a high level. The 2 doses Measles-mumps-rubella combined vaccine (MMR) vaccination could stimulate long-lasting antibody protection. However, lower antibody levels in populations born before China’s NIP implementation, particularly among 17–40 years, suggest an booster vaccination.