A thing I started doing: when people cancel a meeting with me because they don't feel well or just say that they prefer to work from home that day because they are slightly sniffy or their throat is scratchy, I don't just say "sure, no problem" but explicitly thank them.
There is, whether we want or not, pressure that people feel to come to work even if they don't feel 100%. It's important to acknowledge when someone actively works against this.