COVID-19 vaccine dose sparing: strategies to improve vaccine equity and pandemic preparedness

Abstract

Despite tremendous efforts, worldwide COVID-19 vaccination coverage is lagging. Dose-sparing strategies for COVID-19 vaccines can increase vaccine availability to address the global crisis. Several clinical trials evaluating dose sparing are currently underway. However, to rapidly provide solid scientific justification for different dose-sparing strategies, joint coordinated action involving both public and private parties is needed. In this Viewpoint, we provide examples of approaches to vaccine dose-sparing that have previously been evaluated in clinical trials to improve vaccine availability and reflect on the origin of their funding. With a focus on the current COVID-19 pandemic, we stress the need for expedited testing of vaccine dose-sparing strategies in endemic or epidemic infectious diseases. However, we argue that the establishment of a mechanism through which dose-sparing opportunities are systematically identified, scientifically tested, and ultimately implemented will prove to be valuable beyond the current pandemic for infectious diseases product development and pandemic preparedness in the future.

Figure

Vaccine development: conventional, COVID-19, and future pandemics (A) Conventional vaccine development with sequential clinical trial phases followed by regulatory review, production, and distribution. (B) Vaccine development during COVID-19 pandemic whereby clinical trial phases overlap, regulatory authorities apply rolling review procedures, and pharmaceutical companies start production before approval (financial risk partly covered by governments). (C) Optimal future pandemic preparedness with pre-approval phases as in B, after which international public body stimulates and coordinates new trials to evaluate strategies to improve global vaccine access. Promising strategies are evaluated in phase 2/3 trials. Ideally, this evaluation already starts as soon as industry-initiated phase 2 is completed. Parts A and B of this figure are conceptually inspired by Krammer 2020.