This process can be classified into three parts: scientific development, regulatory approval, and production/distribution.
Stage 1: scientific, exploratory. This is where scientists identify natural or synthetic antigens. For coronavirus, these would be virus like particles or weakened viruses. This work is done in the lab and involves animal studies.
Stage 3: regulatory, investigational new drug application. A company applies to the FDA and describes its manufacturing and testing process as well as any summary reports. The FDA has 30 days to approve or reject the application.￼
Stage 4: scientific, vaccine trials. The candidate vaccine is tested on a small group of people (less than 100). If successful, then the candidate vaccine moves to the next stage.￼
Stage five: scientific, vaccine trials. The candidate vaccine is tested on a large group of people (in the thousands or more). This is to look for rare side effects that weren’t presented in the smaller group...
and to see how effective the candidate vaccine is. If successful, then the candidate vaccine moves to the next stage.
Stage 6: regulatory, license and approval. A Biologics license application is submitted to the FDA, which includes investigating production facilities and independent testing. Once approved, vaccine production for the population begins.
Any changes the FDA makes to their approval process can accelerate two out of these seven stages. The other stages are arguably more static and difficult to accelerate. This is why some estimates state a vaccine will take 12 to 18 months.