Vaccines against SARS-CoV-2

The pandemic caused by the novel coronavirus, SARS-CoV-2, first detected in December 2019, resulted in millions of deaths and more than a hundred million confirmed infections in the first 18 months. COVID-19, the disease caused by SARS-CoV-2, is asymptomatic for some, for others it can cause illness ranging from mild flu-like symptoms with the most serious cases manifesting with acute respiratory distress syndrome (ARDS), pneumonia and death. The worldwide effort to develop effective vaccines against COVID-19 and SARS-CoV-2 has been unparalleled throughout history. At the time of writing, there are more than 100 candidate vaccines in clinical development and almost 200 undergoing pre-clinical testing, around the world. These diverse candidates use a range of vaccine strategies and platforms including several relatively novel approaches. Many of these newer strategies have been approved for emergency use and existing data advocate for the critical role that they may have in protecting individuals and reducing the ongoing pandemic. This chapter focusses on nucleic acid and viral vector-based vaccines, currently undergoing post-licensure surveillance, being the most widespread technologies used against the pandemic. As well as reviewing the different vaccine platforms and vaccine candidates, this chapter discusses the events preceding the COVID-19 pandemic that allowed vaccine development to occur at never-before-seen speed, the biological and immunological basis for a SARS-CoV-2 vaccine, the importance of collaborative international efforts and the broad lessons that can be applied towards future pandemics.