If you only know one thing, you keep your mouth shut until you know more. And if the thing you know isn't actually known, like how effective the vaccine really is, that goes double.
Notice that doesn't require you to "know the truth from the beginning in one step." It requires the people in charge to show some restraint.
You only get so many opportunities to be wrong before that trust is eroded.
So hiding and covering up information is the way you think scientists should build trust, rather than being open and also clear about the limitations?
The lack of trust has nothing to do with scientists publishing data and everything to do with hucksters who misinterpret or lie about it to spread anti-vaccine panic or “government control” conspiracy theories.
I blame education for that, for it doesn't properly teach you how to understand science. Science is taught like a Bible, when it should be taught as something people created and it's error prone.
> And if the thing you know isn't actually known
Who do you want to be the arbiter that gatekeeps this information and decides the science is strong enough that you “actually know”?