My growing suspicion is that Trump is being told very directly that he has no chance of a legitimate vaccine-related October Surprise, perhaps not even much of a chance for any "good news" that's exciting enough to announce. He'll still try, I'm sure, but he's just setting himself up for failure, as usual.
I don't expect for the vaccine to be approved until the end of this year-after the election-and as the CDC Director made clear in his congressional testimony yesterday, it will not become widely available to the general public until the second half of next year. So that almost certainly closes another last route of hope for Trump.
Yeah, more and more information seems to indicate that any of these vaccines' longterm effectiveness is unknown. I'm hoping that there'll be better news on that front, but I'm not convinced.