Related question

• When will 1bn people have been vaccinated with any vaccine candidate(s) that have demonstrated an efficacy rate >60% in a n>500 RCT?

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus is a novel betacoronavirus that likely emerged late last year from an animal reservoir in China. There is little to no pre-existing immunity against it in the human population. The clinical picture for the disease it causes, coronavirus disease 2019 (COVID-19), ranges from very mild to fatal. The virus is highly transmissible and has spread globally.

While the development of a vaccine is critical for its successful administration at scale, just as critical is the creation and execution of infrastructure necessary for widescale vaccination to greater than 1 billion people.

The WHO defines vaccine efficacy as follows:

Vaccine efficacy: % reduction in disease incidence in a vaccinated group compared to an unvaccinated group under optimal conditions