Why doesn't every parent catch their child's sick bug?

[Flopsy145]

My 3.5 year old DD is currently down with the dreaded sickness bug, the last two times she's had one I've also come down with it a day or 2 later. But I know a good few parents who never catch it, their kid has 24 hours of sickness and then they just stay healthy. Even my mum never caught mine as a kid and I once threw up on her face.

I'm always diligent with hand washing and Dettol spraying, this time even more so as I'm 35 weeks pregnant and feeling drained enough as it is! We've also been so far pretty lucky and always contained it in a bowl so I'm not (touch wood) so far scrubbing floors or dealing with multiple sicky sheets and towels in the wash.

How do some parents avoid it?!

The only time I can ever recall vomiting in my life is when I was pregnant, and had horrific morning sickness until past 20 weeks. That aside, I've never had a sickness bug that's made me vomit and don't generally get ill, despite the many illnesses DS has brought home from nursery/school over the years. Also never had covid. Presume it's an immune system thing 🤷‍♀️

So far not been sick myself😅🤞🏻 keeping my fingers crossed, she was first sick Thursday afternoon.
Also anyone come across this type of bug before, sick for 14 hours pretty consistently. Then good for almost 48 hours then being sick again after food 🤷🏻‍♀️ she's saying her tummy is sore but I think she's really constipated, no diarrhoea at all one solid poo Friday but keeps trying on the toilet but nothing. Also runny nose, cough and has been a bit hot, had very red cheeks Friday so I was thinking slapped cheek as that's also in her nursery. Or can this be normal for a sick bug?