加拿大麦吉尔大学Caroline E. Wagner等研究人员合作对SARS-CoV-2疫苗给药方案提供了参考依据。该研究于2021年3月9日在线发表于国际一流学术期刊《科学》。

在现有的免疫流行病学模型基础上，研究人员发现在短期内，进行一剂疫苗通常可以减少感染，但长期结果取决于这种相对的免疫耐受性。然后，研究人员探索了三种选择方案，发现一剂策略可能会在部分群体免疫的某些条件下增加抗原进化的潜力。研究人员强调了在接种一剂疫苗后测试病毒载量和量化免疫反应以及加大全世界疫苗接种力度的重要性。

据悉，疫苗剂量面临严重不足，需要部署各种新的策略来提高人群对SARS-CoV-2的免疫水平。目前出现了两个关键问题，通过部分免疫个体的积累，第二剂的给药时间将如何影响感染动力学以及病毒免疫逃逸的进展 。与自然和两剂免疫相比，两者都取决于单剂免疫的稳健性。

附：英文原文

Title: Epidemiological and evolutionary considerations of SARS-CoV-2 vaccine dosing regimes

Author: Chadi M. Saad-Roy, Sinead E. Morris, C. Jessica E. Metcalf, Michael J. Mina, Rachel E. Baker, Jeremy Farrar, Edward C. Holmes, Oliver G. Pybus, Andrea L. Graham, Simon A. Levin, Bryan T. Grenfell, Caroline E. Wagner

Issue&Volume: 2021/03/09

Abstract: In the face of vaccine dose shortages and logistical challenges, various deployment strategies are being proposed to increase population immunity levels to SARS-CoV-2. Two critical issues arise: how will the timing of delivery of the second dose affect both infection dynamics and prospects for the evolution of viral immune escape via a build-up of partially immune individuals. Both hinge on the robustness of the immune response elicited by a single dose, compared to natural and two-dose immunity. Building on an existing immuno-epidemiological model, we find that in the short-term, focusing on one dose generally decreases infections, but longer-term outcomes depend on this relative immune robustness. We then explore three scenarios of selection and find that a one-dose policy may increase the potential for antigenic evolution under certain conditions of partial population immunity. We highlight the critical need to test viral loads and quantify immune responses after one vaccine dose, and to ramp up vaccination efforts throughout the world.

DOI: 10.1126/science.abg8663

Source: https://science.sciencemag.org/content/early/2021/03/08/science.abg8663