兰州大学“聚英萃华”萃英学院学术讲座（第三百九十七场）——何岱海教授

应兰州大学萃英学院邀请，香港理工大学何岱海教授来校举办学术讲座，欢迎全校师生积极参加！

题    目：Modelling COVID-19 vaccine breakthrough infections in highly vaccinated Israel—The effects of waning immunity and third vaccination dose

主讲人：何岱海教授

时    间：5月11日（周日）15：30

地    点：榆中校区致远楼912

主讲人简介：

何岱海，香港理工大学应用数学系教授，博士生导师。分别于1999年获西安交通大学工学博士和2006年加拿大麦克马斯大学数学博士，并且曾在北京师范大学物理系、美国密西根大学生态学系、以色列特拉维夫大学动物学系做博士后研究。主要研究兴趣是传染病建模和数据统计分析，在PNAS, Sci Adv, Ann Intern Med, Eur Respir J, J R Soc Interface等权威期刊发表论文140余篇，研究成果受到国内外媒体的广泛报道。关于非洲安哥拉黄热病的建模获2018年国际疾病监测学会的科学贡献最佳论文第二名；先后获得香港研究资助局项目、香港食品与卫生环境署健康与医疗项目、阿里巴巴合作研究基金等多项基金资助。Google H-index47. 连续三年入选斯坦福大学发布的全球2%顶尖科学家榜单(2022-2024)，以及ScholarGPS2024全球前0.05%学者。

内容简介：

In August 2021, a major wave of the SARS-CoV-2 Delta variant erupted in the highly vaccinated population of Israel. The transmission advantage of the Delta variant enabled it to replace the Alpha variant in approximately two months. The outbreak led to an unexpectedly large proportion of breakthrough infections (BTI)–a phenomenon that received worldwide attention. Most of the Israeli population, especially those aged 60+, received their second dose of the vaccination four months before the invasion of the Delta variant. Hence, either the vaccine induced immunity dropped significantly or the Delta variant possesses immunity escaping abilities, or both. In this work, we model data obtained from the Israeli Ministry of Health, to help understand the epidemiological factors involved in the outbreak. We propose a mathematical model that captures a multitude of factors, including age structure, the time varying vaccine efficacy, time varying transmission rate, BTIs, reduced susceptibility and infectivity of vaccinated individuals, protection duration of the vaccine induced immunity, and the vaccine distribution. We fitted our model to COVID-19 cases among the vaccinated and unvaccinated, for <60 and 60+ age groups, and quantified the transmission rate, the vaccine efficacy over time and the impact of the third dose booster vaccine. The peak transmission rate of the Delta variant was found to be 2.14 times higher than that of the Alpha variant. The two-dose vaccine efficacy against infection dropped significantly from >90% to ~40% over 6 months. We further performed model simulations and quantified counterfactual scenarios examining what would happen if the booster had not been rolled out. We estimated that approximately 4.03 million infective cases (95%CI 3.19, 4.86) were prevented by vaccination overall, and 1.22 million infective cases (95%CI 0.89, 1.62) averted by the booster.