As I always say in threads on this topic, I always wash new things - well, perhaps not a Cardigan or a jumper, but definitely underwear, towels and bedlinen.
They have been stored in warehouses where there could be vermin and then shipped in containers, via other warehouses.
A friend of mine was teaching at a school and one of the girls developed a rash around her waist. They slit open the waistband of her skirt and it was crawling with lice.
My DS2 wore some underpants that I had popped in his Christmas parcel as a stocking filler, without washing them first, despite my advice. He got a bad infection (was literally weeing pus)
I was very shocked when I was in hospital having my first baby. The girl in the bed next to me was a nurse herself. She had even worked on the maternity ward. The flannels she had with her for the baby still had their price tags on them.
My formative years being spent in the Junior Red Cross have left a lasting impression on me with regard to hygiene.