Sick newborn😪

My niece and nephew that live with me are sick. They have a cold with runny nose and bad cough. I try to keep my baby away from them but they always want to be around her. Now my baby who is 5 weeks old is having congestion and boogers. Idk if shes sick and if she is what should i do? I feel so bad that she has a cold already so little 😞