More flexible working options would definitely improve the situation.
I had an awful cold plus dizziness virus earlier in the year.
First day lost my voice entirely very suddenly, no other symptoms. Had some lieu acquired, so just took Friday afternoon off to read. I could have worked, but preferred not to, and couldn't say a word to anyone, and there was no urgent work.
Come the Monday, had progressed to dizziness so bad I couldn't stand. I worked from home half the day on something that couldn't wait. I definitely wasn't firing on all cylinders, and had to redo some of the work later. Ended the day wiped, throbbing head, the works.
Took the full Tuesday off. Felt better at the end.
Worked from home Weds, worked two short days in the office Thursday and Friday.
On the one hand just a cold. On the other, something that seriously knocked me out.