We saw an improvement last winter when we started our LO on probiotics, he was on vitamins already and this winter he's only had 1 bug so far. We also carry children's hand sanitizer for when we can't wash hands
Probiotics, really healthy diet (we are vegetarians, so eat a lot of tofu, beans and pulses), wash hands after being out and about, multivitamins (we use avacare)💝
Don't think it can be avoided, unless well you keep locked away. I feel for you tho caz my parents are planning on visiting us but my mums immune system isn't great and will catch things easy and bad... we are currently "recovering" from a nasty cold. My youngest catches things really easily too. Only way to reduce things is to stay home but we know it's not possible when you have things to do or others in the household have to be out.