A living evidence approach to variants of concern (VOC) and COVID‑19 vaccine effectiveness
The rapid development of safe and effective COVID‑19 vaccines is an outstanding scientific achievement. As an increasing proportion of the world’s population is vaccinated, societies have begun to regain some form of normalcy. However, it is evident that COVID‑19 will remain a serious public health concern in the coming years, largely driven by variants of concern (VOC – virus mutants with increased spread and/or severity of disease and/or decreased vaccine effectiveness). In many regions the majority of new cases are due to VOC. It is critical to continuously monitor vaccine effectiveness against VOC (e.g., breakthrough infection rates, transmission rates). Systematic surveillance of the rapidly evolving scientific evidence base is necessary to inform public health action and research aimed at improving the use of current vaccines and development of vaccines and/or boosters. Living evidence syntheses use rigorous scientific methods to identify, appraise and summarize evidence, proving their usefulness when the evidence base is rapidly developing and bears significant policy and practice importance. Since April 2021 we have deployed 15 editions of a living review to determine the effects of VOC on vaccine efficacy, regularly communicated to PHAC and HC among others. We will extend this series, also considering additional outcomes such as immunity duration, new emerging VOC and new vaccines. We will search the global peer-reviewed and grey literature daily, update our synopsis weekly, and our full synthesis on at least a monthly basis. We will maintain an up-to-date summary of our findings on our website (including plain language summaries in French and English) and disseminate at least monthly briefings through our networks of decision makers. Our living evidence summaries will ensure that citizens, healthcare and public health professionals and policy makers continue to have access to timely trustworthy evidence to inform their decisions in response to VOCs.