Ha ha. We've all worked with someone like that.
People often boast of never having a sick day in x number of years but that usually means at least one of three things: they've got a flawless immune system, they regularly go into work ill and spread their germs, or they book annual/flexi leave when they're unwell.
It's a bit different if you can work from home or don't get sick pay, and we've all gone into work with colds or whatever before, but sometimes you just have to take sick days. If it's a regular thing it's a problem but people who come in with all kinds of viruses are more part of the problem than model employees and end up causing more staff absences than they solve and expect a medal for it.
In my second significant job I was a manager for the first time, and I remember one of the staff for whom I worked as a manager coming to work with a cold or something similar, I told him (nicely, I assure you!) to go home and not to come back to work until he was over it, if he wanted to do some work from home and it was appropriate then that'd be fine but otherwise work wasn't important enough that it couldn't wait.
I think I did this especially because I'd suffered 22 years in my first significant job with people coming to work ill and telling everyone what heroes they were at the same time as infecting everyone else, so in my second job I realised I could do something about it!
Sorry, this is getting off-topic now, I'll shut up about sneezing!