It depends on what's going on hiatus--if it's social media, then you're not going to see a huge drop. People only notice your gone if you make a post about "sorry I'm gone" like...just don't do that and take a break, you'll be fine. Especially during this year when basically everyone is taking a break. I've had like...a month hiatus a few times this year on twitter and lost maybe 2 followers. (and gained more than two when I started posting again) you're fine, so long as you don't post negative stuff all the time about it and have a public melt down, just keep it positive and go with the flow when you're ready.
As for comics, I have heard that the algorithm bites your ass if you go off schedule--but for me I have a small following, so I announced on my wall I was going to take a little break for a few weeks--ppl seemed chil about it and no one left (I didn't make a post in the comic or anything--I did that once, I made a post that was like "I'm going on a short hiatus!" and lost like 2 subs that update). When I came back, I felt refreshed and stats went back to normal after a week or so.
I didn't take a very long hiatus, though, only a few weeks. Now I will say I ended my comic and then several months later posted a new update--and that update (it's an inktober incentive) has a huge boost of views compared to what I made before it, since I made this inktober update really shiny and pretty, so honestly I don't think it matters so long as you don't make a big deal out of it, and come back with content that is pretty and fun to read.