Most of the time, we use the sick bay for students who have a contagious disease, until they can be sent home. The sick bay is only used as a temporary measure. It's parents who must bear the greatest responsibility. (@Vilemar, is there any viral outbreak in your place at this time?)
Have a look at this recent news: "Abu Dhabi: An Emirati lawyer at the Abu Dhabi Public Prosecution lost one of his children while vacationing in Malaysia with his family during Ramadan. Speaking to Gulf News, Counsellor Omar Bkheit Al Gafili told the harrowing tale of how what started as a seemingly harmful cough ended up taking his three-month-old daughter’s life. The victim Galia’s twin sister, who also seems to have caught a Respiratory Syncytial Virus (RSV), a common illness among children, is now being treated at the Shaikh Khalifa Medical City (SKMC). Her condition is stable."
While anyone can catch the flu, certain groups—including school-aged children—are at a higher risk. This is partly because children are exposed to a variety of germs each day at school. Germs can be spread through hand-to-hand contact and by touching contaminated surfaces. Kids often contract the flu from other children who are carrying the virus, or when they come into contact with toys, desks, or playground equipment that may be harboring germs. Indeed, many children are likely to return home sick after only a few days or weeks at school.
Thanks for the question. I think they should be isolated/kept home till recover. The teacher can support them by private tutoring during office hours to cover the material they have missed during sickness.
Answering your question: What to do if both parents need to work?
Possible option is is to use a babysitter at their home since using a daycare will end up with the same problem (spreading the disease). Another option is to use relatives like father in law, mother in law, ..etc to take care of them for some time till they recover. Most important is to isolate them from other children since in general children have weak immune system and they can catch diseases easily. If these children are not isolated then the problem will be magnified and more families will have to find a solution to their sons'/daughters' illness.
A most difficult time, in school, is when children head back to packed classroom which may contain a student or more with a contagious viral disease. I experienced this problem when I taught in a refugee camp school in Jordan long time ago. Saying to the kid "Go & stay at home when you are sick" is easier said than done because his poor father or mother will come to you next morning to protest against separating the child from school life in the first few days or weeks. I think that a medical doctor ought to come to school & order the student's leave; this is not the job of the teacher or the school's headmaster.
Children should be away from school, till the last blister falls. There can be nothing more soothing than a mother's presence and love or else someone to give care.
Dear colleagues, if it's absolutely necessary that students who have viral ailments be in class, they should be wearing masks, and so should other students. (Here, I have been wearing a mask because of the bad air quality (haze) due to fires in Indonesia.)
"For many years, scientists weren't sure if wearing a mask was effective at preventing the spread of viruses. However, recent studies suggest that they can help."