Here, it’s up to your employer how much “personal time off” you’re allowed each year (they don’t call it “sick time” any more), and it’s up to your employer how it’s managed.
For example, the last place MrsT worked for an employer, she got something like 40 hours a year in PTO (so, a week), but what she didn’t use could be banked indefinitely. That’s how her coworker, when she got breast cancer, was able to take a solid five months off work with pay and no threat of job loss. She’d saved her PTO for years and rarely used it.
The downside of that, of course, is that it incentivizes people to come to work with colds, the flu, etc and get everyone else sick, because they don’t want to use their PTO.
For me, I get 48 hours PTO a year, and that’s it - it doesn’t roll over year after year, so there’s no reason not to take it, so sick or not, I take mine.
Of course, with MrsT’s and my own health issues, it’s getting easier and easier to burn through that 48 hours in no time. 10 years ago, I’d look for reasons to call off work for a day, just to keep from losing a free day off, but now, it’s more like, “Here it is August and I’ve already used all my PTO - guess I have to dip into my vacation time to get over Covid this year.”