“Will that require another booster?”
Why not? The “booster” is the same shot you already got. It’s not for Delta, or any other variant.
The “booster” is just a little “boost” for you. To get your immune system into high gear, looking for little spikes, again. It’s the wrong spike, but it does get your system on the lookout.
Of course, it would be some actual improvement in immunity to “vaccinate” for the actual Delta spike, but that development would probably take years. Just like the original.
My opinion and understanding, of course.
How often for a booster?
Is the vax only 39% effective against delta because it’s a variant or because of time?
Either way, this is a dumpster fire in progress.
Coronaviruses and the flu mutate and circle the globe forever.