Wu Yanpeng, Wang Qianli, Wang Wei, Zhou Xiaoyu, Zhang Juanjuan, Zhao Sihong, Liang Yuxia, Wang Pengfei, Trentini Filippo, Ajelli Marco, Yu Hongjie
Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai, China.
School of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, China.
Open Forum Infect Dis. 2025 Apr 8;12(5):ofaf216. doi: 10.1093/ofid/ofaf216. eCollection 2025 May.
Assessing the measles immunity profile is critical for developing effective nationwide or regionwide supplementary immunization activities (SIAs). This study aims to assess measles population immunity levels in China and investigate factors contributing to age-specific heterogeneities.
We conducted a cross-sectional population-based serological study in southern China between June and October 2021. We determined the population mean antibody concentration and seroprevalence by age and over time, along with their associated determinants. Moreover, we estimated the contact-adjusted immunity levels by considering both age-specific immunity levels and population contact rates.
Among the 1015 study participants (aged 0-95 years), the overall seroprevalence was estimated at 80.9% (95% confidence interval [CI], 78.3-83.3). When adjusting for the age-specific contact rates, the contact-adjusted immunity was estimated at 66.8% (95% CI, 56.6-75.1). Individuals younger than age 30 years showed significantly lower antibody concentration and seroprevalence (mean log concentration: 5.9, seroprevalence: 73.6% [95% CI, 69.9-77.3]) compared to those older than age 50 years (mean log concentration: 6.8, seroprevalence: 96.8% [95% CI, 94.7-98.9]). In particular, individuals born after the last SIA (2010) showed a significantly faster waning of immunity.
Our findings highlight that immunity levels in the general population remain below the 95% threshold, underscoring the need for continued monitoring of immunity dynamics, especially for individuals born in a near-elimination setting and without subsequent SIAs.
评估麻疹免疫状况对于开展有效的全国性或地区性补充免疫活动（SIAs）至关重要。本研究旨在评估中国人群的麻疹免疫水平，并调查导致年龄特异性异质性的因素。
2021年6月至10月，我们在中国南方开展了一项基于人群的横断面血清学研究。我们按年龄和时间确定了人群平均抗体浓度和血清阳性率及其相关决定因素。此外，我们通过考虑年龄特异性免疫水平和人群接触率来估计接触调整后的免疫水平。
在1015名研究参与者（年龄0至95岁）中，总体血清阳性率估计为80.9%（95%置信区间[CI]，78.3 - 83.3）。在调整年龄特异性接触率后，接触调整后的免疫率估计为66.8%（95%CI，56.6 - 75.1）。与50岁以上人群（平均对数浓度：6.8，血清阳性率：96.8%[95%CI，94.7 - 98.9]）相比，30岁以下个体的抗体浓度和血清阳性率显著较低（平均对数浓度：5.9，血清阳性率：73.6%[95%CI，69.9 - 77.3]）。特别是，上次补充免疫活动（2010年）后出生的个体免疫下降明显更快。
我们的研究结果表明，普通人群的免疫水平仍低于95%的阈值，这突出表明需要持续监测免疫动态，特别是对于在接近消除麻疹背景下出生且未进行后续补充免疫活动的个体。
