COVID-19 vaccine development pipeline gears up

Abstract

Vaccine development is typically a long game. The US Food and Drug Administration only approved a first vaccine against Ebola virus last year, 43 years after the deadly virus was discovered. Vaccinologists have made little headway with HIV or respiratory syncytial virus, despite huge investments. On average, it takes 10 years to develop a vaccine. With the COVID-19 crisis looming, everyone is hoping that this time will be different. It might be. Already, ten vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) are in clinical trials (table), and researchers at the University of Oxford and AstraZeneca hope to have the first phase 3 data in hand this summer. Although many infectious disease experts argue that even 18 months for a first vaccine is an incredibly aggressive schedule, a few optimists believe that hundreds of millions of doses of vaccine might be ready for roll-out by the end of 2020. “What’s happened so far has been nothing short of amazing”, says Penny Heaton, a vaccinologist and chief executive officer (CEO) of the Bill & Melinda Gates Medical Research Institute. Previous investments in new vaccine technology platforms made this possible, she adds. Indeed, several of the most advanced vaccine candidates make use of emerging technology platforms. Moderna’s mRNA-1273, which entered into clinical trials just 66 days after SARS-CoV-2 was first sequenced, showcases the potential for nucleotidebased vaccines. Like traditional livevirus vaccines, these vaccines deliver a genetic sequence into a host cell, and co-opt host machinery to express antigens of interest. However, rather than using a weakened SARS-CoV-2 to transport the code, Moderna’s vaccine uses a synthetic lipid nanoparticle to carry mRNA templates. Like most other COVID-19 vaccines in development, Moderna’s candidate attempts to train the immune system to recognise SARS-CoV-2’s spike protein, which the virus uses to bind to and enter host cells.