If the kids are not seriously ill, you should take them out to run and enjoy the sunshine. Doctors suggest me to take my children out for sunshine and exercises. They will recover from illnesses sooner after sweating. Of course, you have to take a dry towel with you to dry their sweat before the breezes come.
Children will build up more antibodies as time goes by. Feed them more healthy and natural food. Don't worry and stay optimistic.