Stollenwerk Nico, Estadilla Carlo Delfin S, Mar Javier, Bidaurrazaga Van-Dierdonck Joseba, Ibarrondo Oliver, Blasco-Aguado Rubén, Aguiar Maíra
BCAM-Basque Center for Applied Mathematics, Bilbao, Basque Country, Spain.
Dipartimento di Matematica, Universitá degli Studi di Trento, Povo, Trento, Italy.
Infect Dis Model. 2023 Jun;8(2):318-340. doi: 10.1016/j.idm.2023.03.002. Epub 2023 Mar 10.
Vaccines have measurable efficacy obtained first from vaccine trials. However, vaccine efficacy (VE) is not a static measure and long-term population studies are needed to evaluate its performance and impact. COVID-19 vaccines have been developed in record time and the currently licensed vaccines are extremely effective against severe disease with higher VE after the full immunization schedule. To assess the impact of the initial phase of the COVID-19 vaccination rollout programmes, we used an extended Susceptible - Hospitalized - Asymptomatic/mild - Recovered () model. Vaccination models were proposed to evaluate different vaccine types: vaccine type 1 which protects against severe disease only but fails to block disease transmission, and vaccine type 2 which protects against both severe disease and infection. VE was assumed as reported by the vaccine trials incorporating the difference in efficacy between one and two doses of vaccine administration. We described the performance of the vaccine in reducing hospitalizations during a momentary scenario in the Basque Country, Spain. With a population in a mixed vaccination setting, our results have shown that reductions in hospitalized COVID-19 cases were observed five months after the vaccination rollout started, from May to June 2021. Specifically in June, a good agreement between modelling simulation and empirical data was well pronounced.
疫苗的可测量疗效首先来自疫苗试验。然而，疫苗效力（VE）并非一成不变的衡量标准，需要进行长期的人群研究来评估其性能和影响。新冠疫苗在创纪录的时间内研发出来，目前已获许可的疫苗在完成全程免疫接种后对重症疾病极为有效，疫苗效力更高。为评估新冠疫苗接种推广计划初始阶段的影响，我们使用了一个扩展的易感-住院-无症状/轻症-康复（SHARM）模型。我们提出了疫苗接种模型来评估不同类型的疫苗：1型疫苗仅预防重症疾病但无法阻断疾病传播，2型疫苗既预防重症疾病又预防感染。疫苗效力按照疫苗试验报告的情况假设，纳入了一剂和两剂疫苗接种效力的差异。我们描述了在西班牙巴斯克地区的一个瞬时情景中，疫苗在减少住院方面的表现。在混合接种疫苗的人群中，我们的结果显示，在2021年5月至6月疫苗接种推广开始五个月后，新冠住院病例有所减少。具体到6月，模型模拟与实证数据之间的良好一致性非常明显。
