Phase I: 24
Phase 2: 14
Phase 3: 9
Limited approval: 3 (CanSinoBio, Gamaleya Research Institute (Russia), Sinovac)
Full approval: 0
That's not even including the hundred or so still in lab or animal testing. It's encouraging; something is likely to work.
The real question is, how effective are the ones that make through the safety tests? Nobody really knows yet. The FDA (pre-Trump push) announced that their minimal effectiveness for approval was 50%, which is low for a vaccine. Moderna is aiming for 60%. Effectiveness times fraction of population getting it has to be > 70% or so to stop the epidemic with a vaccine alone. That's the "herd immunity" fraction for a disease with a growth rate of 3.
Useful questions:
- If a vaccine is only partially effective, will an antibody test tell if it worked?
- Will taking one vaccine limit the effectiveness of another vaccine taken later? That's happened for a few vaccines.[2] It's usually more of a timing thing; some vaccines should not be given within a few weeks of other vaccines.[3]
- Could widespread use of a moderately effective vaccine cause people to abandon mask-type precautions and cause an epidemic spike in the unprotected part of the population?
Is someone working those issues effectively?
[1] https://www.nytimes.com/interactive/2020/science/coronavirus...
[2] https://www.tandfonline.com/doi/pdf/10.1080/21645515.2015.10...
[3] https://www.ok.gov/health2/documents/IMM_PRG_5-20_Intervals_...