Calling in sick on first day?

A general rule: Try not to miss your first week.

Unless you think you've got Covid, take some Nyquil and get your butt to work.

You should never call in sick on your first week unless you absolutely have to, just get a covid test and make sure you wear a mask if you're still sneezing or have a runny nose by then so they don't think that you just don't care about covid safety.

I would not call out on my first day thats not a good look at all

Get covid test and if if it comes clean you can honestly say it's just a cold and go in.

It doesn't sound like much, I'd say you'd be fine. But get a covid test anyway, then if it comes back negative you can go. Usually it would obviously be bad to call in sick on your first day, but not now with covid. It'd be really bad for you to go in when you're clearly sick. It'd show that you don't care about covid safety at all. And it'd certainly be much worse if you infect everyone there with covid.

Doesn't look good.

I would call the person that hired you or personally go see them.
If you are really sick, besides getting the covid test, I would just ask to move back my start date by a week or at least three days. That way it doesn't count against you and you're not using the start date for benefits or seniority purposes.

A week or few days will give enough time to recover and not go into work sick.

Take a lateral flow test and if it’s negative you should definitely go in. You might feel completely better in a few days anyway.

Is it possible that you’re trying to delay starting because you’re nervous?

Go in. It sucks but your employer will appreciate the effort. If you look decrepit enough where your employer tells you to go home then you are clear.

If you are seriously ill, then its best to call in.

I was once going to start a job... and called them from the hospital the day before explaining that I was in the hospital. Not a problem at all - nor was week at home after that or my daily trips for another week (2 weeks total) after I was free to leave home for IV antibiotics after I got out of the hospitable.

I did have my laptop with me and I was actually able to start some of the work while I was in the hospital though. They appreciated that.

It sucks but sometimes you have to work when sick especially if it's an important week in this case your first. I'm sure by then you'll feel at least half better. Just take care of yourself as much as possible until then. Vitamin C, rest, stay hydrated etc.