We believe there is good reason to be optimistic. The global effort to develop a vaccine for COVID-19 has progressed at an incredible speed and is breathtaking when put in the context of vaccine development, which typically takes around a decade.
When we consider the likelihood of success for any single vaccine program, the analysis is perhaps a little sobering. Drug development is an intensely complex process where any single effort is much more likely to fail than not; a common rule of thumb is that only 1 in 10 drug development projects that enter the clinic ultimately produce an approved drug. That said, we should be encouraged that vaccines for infectious diseases seem to enjoy substantially higher success rates than other areas, such as oncology. A 2018 study put the vaccine success rate at 33% vs. 13% for all areas.
We believe there is good reason to be optimistic. The pipeline of vaccine candidates is impressive, with over 160 programs and counting, including 13 that are in the clinic, several of which progressed into large late-stage Phase 3 trials in July. Three companies are also discussing the prospect of an emergency-use approval by the end of the year.
One encouraging feature of the pipeline is the diversification in approaches, as highlighted below. The benefit here is that if any one candidate fails, it is less likely to be for technological reasons that might throw doubt on similar projects. However, we should note that nearly half of these efforts are coming in novel areas (such as genetic vaccines) that have limited or no prior use in large-scale vaccine programs.