Because, there are multiple teams of companies and scientists around the globe, that all report that they'll have candidates ready in the very near future, i.e.

Because, there are multiple teams of companies and scientists around the globe, that all report that they'll have candidates ready in the very near future, i.e. 3-4 weeks. Which means they are convinced the vaccines work. But since vaccines are given to a large number of people, you have to make sure that there is a very low number of adverse effects. And that takes most of the time. But the vaccine candidates are almost ready.