Students are justified because of seasonal flu, so it doesn't spread to school

Parents have been advised by the school principal that if students show flu symptoms, let them check with the doctor.

This is a full announcement from the school:

Honored parents, many cases of students with seasonal flu have increased in recent days, so if students show flu symptoms, let them check the doctor's attention and safety that the flu does not spread its absence at school is recommended and will be rational!
Dear students, masks continue to be mandatory all the time you stay in school!