If 90% of people who catch covid-19 are asymptomatic, then a 90% effective vaccine is basically a placebo.
Not a placebo, you are no longer a vector for transmission.
The bigger issue is the accuracy of the tests
That means no drug company truly knows how effective their vaccine is because the results of the vaccine might be the same results as among the normal population
Clinical trials with follow-up have this covered.
Fake news on that one. See total deaths chart: http://prntscr.com/vv4l1e