Farhang-Sardroodi Suzan, Korosec Chapin S, Gholami Samaneh, Craig Morgan, Moyles Iain R, Ghaemi Mohammad Sajjad, Ooi Hsu Kiang, Heffernan Jane M
Modelling Infection and Immunity Lab, Mathematics Statistics, York University, Toronto, ON M3J 1P3, Canada.
Centre for Disease Modelling (CDM), Mathematics Statistics, York University, Toronto, ON M3J 1P3, Canada.
Vaccines (Basel). 2021 Aug 4;9(8):861. doi: 10.3390/vaccines9080861.
During the SARS-CoV-2 global pandemic, several vaccines, including mRNA and adenovirus vector approaches, have received emergency or full approval. However, supply chain logistics have hampered global vaccine delivery, which is impacting mass vaccination strategies. Recent studies have identified different strategies for vaccine dose administration so that supply constraints issues are diminished. These include increasing the time between consecutive doses in a two-dose vaccine regimen and reducing the dosage of the second dose. We consider both of these strategies in a mathematical modeling study of a non-replicating viral vector adenovirus vaccine in this work. We investigate the impact of different prime-boost strategies by quantifying their effects on immunological outcomes based on simple system of ordinary differential equations. The boost dose is administered either at a standard dose (SD) of 1000 or at a low dose (LD) of 500 or 250 vaccine particles. Results show dose-dependent immune response activity. Our model predictions show that by stretching the prime-boost interval to 18 or 20, in an SD/SD or SD/LD regimen, the minimum promoted antibody (Nab) response will be comparable with the neutralizing antibody level measured in COVID-19 recovered patients. Results also show that the minimum stimulated antibody in SD/SD regimen is identical with the high level observed in clinical trial data. We conclude that an SD/LD regimen may provide protective capacity, which will allow for conservation of vaccine doses.
在严重急性呼吸综合征冠状病毒2（SARS-CoV-2）全球大流行期间，包括信使核糖核酸（mRNA）和腺病毒载体方法在内的几种疫苗已获得紧急或全面批准。然而，供应链物流阻碍了全球疫苗配送，这正在影响大规模疫苗接种策略。最近的研究确定了不同的疫苗剂量接种策略，以便减少供应限制问题。这些策略包括在两剂疫苗接种方案中增加连续剂量之间的时间间隔，以及减少第二剂的剂量。在这项工作中，我们在一项关于非复制型病毒载体腺病毒疫苗的数学建模研究中考虑了这两种策略。我们通过基于简单的常微分方程组量化不同的初免-加强策略对免疫结果的影响，来研究其影响。加强剂量以1000的标准剂量（SD）或500或250个疫苗颗粒的低剂量（LD）给药。结果显示出剂量依赖性免疫反应活性。我们的模型预测表明，在SD/SD或SD/LD方案中，通过将初免-加强间隔延长至18或20，最低促进抗体（Nab）反应将与在新冠康复患者中测得的中和抗体水平相当。结果还表明，SD/SD方案中最低刺激抗体与临床试验数据中观察到的高水平相同。我们得出结论，SD/LD方案可能提供保护能力，这将有助于节省疫苗剂量。
