Ovex then 10 days later another dose as it only kills the worms not the eggs so the eggs that are there will hatch and you won't get rid of them. You need to break the life cycle. So really good hand hygiene, no hands in mouth. Scrupulous cleaning for 2 weeks. All surfaces, bedding, towels etc on hot wash. Good hoovering. Throw toothbrushes away, get new ones and put them in a cupboard, not left in the open. Scrub nails with nail brush every morning. Keep nails short. Fresh underwear at bedtime. Tight fitting pants or onesies so they can't get to their bottoms to itch. No flinging underwear and clothes across the room, eggs will fly everywhere. Shower first thing in morning to wash way the eggs as the worms come out at night and lay their eggs so they need to be washed away in the shower first thing. Make sure door handles are clean and light switches. The eggs can be on every surface. Picked up on fingers, fingers in mouth, ingest eggs, problem.
I had a hellish two weeks cleaning and changing beds every day, nagging the kids constantly not to put hands in their mouths, making them wash their hands as soon as they came into the house, watched them like a hawk washing their hands after toilet etc and before meals. We got rid of them and I've backed off a bit but I'm still very hot on good hand hygiene and keeping the house as clean as I possibly can with a toddler and a school child!