After the reported high efficacy of the Biontech/Pfizer and Moderna (mRNA) vaccines and the rather more modest results (overall, excluding the small subgroup in the UK that received half/full dose regime and consisted of mainly white persons all below 55) there has been setbacks with two other potential vaccines. The Sanofi-GSK vaccine was found to poorly protect elderly people (aged>49) and phase III trials with an improved (?) vaccine will now start in the 2nd quarter of 2021. This means that the vaccine -if successful- will not be available till the end of 2021 .https://www.statnews.com/2020/12/11/sanofi-suffers-major-setback-in-development-of-a-covid-19-vaccine/.

The Australian CSL-UQ vaccine has been dropped completely as a component of the vaccine gives false positive HIV-tests https://www.bbc.com/news/world-australia-55269381. Actually some scientists had already warned about this problem based on early tests with monkeys.  However, with the Australian Govt having ordered 51 million doses (!), they doggedly continued development.

 

This is not unexpected...for vaccine development in general, something on the order of 9 out of 10 candidates are found to be ineffective (or have unacceptable side effects). It will be interesting to get more efficacy date on the Sputnik and SinoVac vaccines (Indonesia has reported very good results and approved in UAE).