Other than Billy Batson, we don’t know yet. However, Year of the villain gave us a list of 20ish suspects. Shazam being one of them.
I know I’m not the only one who thought Metal royally sucked. So I’m avoiding this whole run.
@harley.333 But have you been reading The Batman Who Laughs miniseries? It’s been great so far. Just because you don’t like the event that certain characters came from doesn’t mean that the characters can’t move on to better things that you may enjoy more.
Yeah, I know. It was just, so bad…
But I read Bloodlines back in the day. If I can make it through that, I can make it through anything!
To give credit where due, the question was posed by DC themselves in the article that link goes to and on the image (once you click it) in my OP, not me. 
This image reminds me of the promo images they did during Countdown to Final Crisis and Final Crisis itself. They had all manner of items strewn about, things that might (but not always) be a clue to something big in a story.
I’m hopeful the image above is a return to that type of marketing as it was fun to speculate about what could be forthcoming in a story.
Example: why is the Wally West Flash wearing a scarf in the above promo image? Jaime Reyes is displayed prominently, is he a key figure in something? It’s fun to guess.
Ha. Bloodlines was awful.
I’m sure everyone noticed this already, but the infected in this “before” poster (without spoiling) all have something in common.