Trinaj - it's a real pain, isn't it. DD2's class goes through infestations like that, but luckily DD2 has only had them twice.
We were advised by the local health board to do a total 'detox' at home to make sure they weren't lurking on sheets, hats etc.
So apart from what you're doing - treatment plus nitty gritty combing, we:
treated and combed everyone in the house.
Combed every single day, then did a second treatment after a week to kill any hatched nits.
washed every sheet and duvet cover in the house at 60 degrees.
washed the sofa cover at 60 degrees (if non-washable then clean sofa using some spray stuff I think nitty-gritty also sells).
washed over the car headrests and car seats
washed all hats and scarves at 60 degrees
all soft toys and other non-washable but textile things went in sealed plastic bags in the shed (or cellar or attic) for one week. Also textiles waiting to be washed.
children chose one soft toy each, which went in the freezer for 24 hours.
all brushes, combs and bobbles went in freezer for 24 hours.
You might think this is well over the top, but it's the current advice in Germany, and both times we got rid of the lice straight away. The second infection was months after the first and we know the source.