Department of Computer Science, Applied Mathematics, and Statistics, Universitat de Girona, Catalonia, Spain.
Department of Electrical and Computer Engineering, Kansas State University, Manhattan, KS, USA.
Sci Rep. 2022 Feb 16;12(1):2640. doi: 10.1038/s41598-022-06477-0.
Currently, several western countries have more than half of their population fully vaccinated against COVID-19. At the same time, some of them are experiencing a fourth or even a fifth wave of cases, most of them concentrated in sectors of the populations whose vaccination coverage is lower than the average. So, the initial scenario of vaccine prioritization has given way to a new one where achieving herd immunity is the primary concern. Using an age-structured vaccination model with waning immunity, we show that, under a limited supply of vaccines, a vaccination strategy based on minimizing the basic reproduction number allows for the deployment of a number of vaccine doses lower than the one required for maximizing the vaccination coverage. Such minimization is achieved by giving greater protection to those age groups that, for a given social contact pattern, have smaller fractions of susceptible individuals at the endemic equilibrium without vaccination, that is, to those groups that are more vulnerable to infection.
目前，一些西方国家已经有超过一半的人口完全接种了 COVID-19 疫苗。与此同时，其中一些国家正在经历第四波甚至第五波病例，其中大多数集中在疫苗接种率低于平均水平的人群中。因此，最初的疫苗优先接种方案已经让位于一个新的方案，即实现群体免疫是首要关注点。我们使用具有免疫衰减的年龄结构疫苗接种模型表明，在疫苗供应有限的情况下，基于最小化基本繁殖数的疫苗接种策略允许部署的疫苗剂量低于最大化疫苗接种覆盖率所需的剂量。这种最小化是通过为那些在给定的社会接触模式下，在没有接种疫苗的情况下，在地方病平衡时易感个体比例较小的年龄组提供更大的保护来实现的，也就是说，为那些更容易感染的群体提供更大的保护。
