Mehra Somya, Kludkleeb Sajikapon, Chaimayo Chutikarn, Leaungwutiwong Pornsawan, Lawpoolsri Saranath, Pan-Ngum Wirichada, Chokephaibulkit Kulkanya, Ngamprasertchai Thundon
Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand.
Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
Lancet Reg Health Southeast Asia. 2024 Dec 21;32:100523. doi: 10.1016/j.lansea.2024.100523. eCollection 2025 Jan.
In highly measles immunized countries, immunity gaps in adolescents and young adults are a key issue posing an obstacle to measles elimination. This study aims to identify the gaps by estimating the age-stratified probability of seropositivity, and to ascertain a suitable age for the administration of a third dose of a measles-containing vaccine (MCV3) to effectively fill these gaps.
We retrospectively obtained measles serological results from hospital setting among among individuals aged 13-39 years and developed a serocatalytic dynamic probability model, stratifying seropositivity due to vaccination or natural infection. We calibrated the model to age-stratified seropositivity data within a Bayesian setting using the Metropolis-Hastings algorithm. A scenario analysis to determine a suitable age for MCV3 administration was also performed.
The overall prevalence of measles seropositivity was 65.6% (95% confidence interval [CI]: 61.5-69.6). Posterior predictive curves for the age-stratified seroprevalence exhibited a decreasing trend from ages 13-20 years but an upward trend from 26 to 30 years. The age at which a given individual's serostatus reached a 50% probability of seronegativity was found to be approximately 18-20 years depending on the annual measles force of infection.
Our findings highlight a significant measles immunity gap in young adults aged 20-26 years, posing an increased risk of transmission. A MCV3 at the age of 18-20 years potentially closes the gap and aids measles elimination programmes.
This work was supported by Faculty of Tropical Medicine (MCTM, ICTM grant), Mahidol University (to T.N.) and APC fee was supported by Mahidol University (to T.N.). S.M. and W.P. were funded in whole, or in part, by the Wellcome Trust [Grant number 220211]. For the purpose of open access, the authors have applied a CC BY public copyright licence to any Author Accepted Manuscript version arising from this submission.
在麻疹高免疫国家，青少年和青年成人中的免疫差距是消除麻疹的一个关键问题，构成了障碍。本研究旨在通过估计年龄分层的血清阳性概率来确定这些差距，并确定接种第三剂含麻疹疫苗（MCV3）以有效填补这些差距的合适年龄。
我们回顾性地从医院环境中获取了13至39岁个体的麻疹血清学结果，并建立了一个血清催化动态概率模型，将因接种疫苗或自然感染导致的血清阳性进行分层。我们使用Metropolis-Hastings算法在贝叶斯框架内将模型校准到年龄分层的血清阳性数据。还进行了情景分析以确定MCV3接种的合适年龄。
麻疹血清阳性的总体患病率为65.6%（95%置信区间[CI]：61.5 - 69.6）。年龄分层血清阳性率的后验预测曲线在13至20岁呈下降趋势，但在26至30岁呈上升趋势。根据年度麻疹感染强度，发现给定个体血清状态达到血清阴性概率为50%的年龄约为18至20岁。
我们的研究结果突出了20至26岁青年成人中存在显著的麻疹免疫差距，这增加了传播风险。18至20岁接种MCV3可能会缩小差距并有助于麻疹消除计划。
这项工作得到了玛希隆大学热带医学院（MCTM，ICTM资助）的支持（给T.N.），APC费用由玛希隆大学支持（给T.N.）。S.M.和W.P.全部或部分由惠康信托基金资助[资助编号220211]。为了实现开放获取，作者已对本提交产生的任何作者接受稿件版本应用了CC BY公共版权许可。
