Covid 19 test after 7 days still positive

I was so worried that under moh and ecda advisory they allow tested positive people going school. My children both less than 3 years old. What if the staff still positive even after 7 days, children immune system still so weak ): ! Children really will be fine? Me and my husband need to work, I can don't send for 1 or 2 days but not always. Can anyone say something to reassure me TiA!