Is this how to respond?
http://clashdaily.com/2017/09/watch-girl-plows-teacher-right-kisser-teachers-response-weird/
Just the clip
Like the article reads, it is school policy. The attacker may have a mental disorder. Kids with all kinds of issues go to public schools. Some of these kids are so bad off that they have one on one assistants with them the entire day. It's not uncommon for school personnel to be injured by students.

Dealing with Violent Behavior
In case of assault, ensuring the safety of others
Try to avoid responding physicallyIf you have to respond physically to defend yourself or others, you should use reasonable force given the student’s age, size, and ability to inflict injury.
Be sure the situation is stable and that a qualified individual assumes supervisory responsibility for your students.
Contact the school nurse
Immediately identify and record the names, addresses, and phone numbers of all witnesses, location, time of incident, and the facts surrounding the teacher.
In case of assault with personal injuryCall the appropriate association and request assistance
Immediately report the incident to the school administration
Ask for medical diagnosis and treatment
Request that the association assist you in obtaining immediate sick leave and go immediately to your doctor
The doctor should know and understand that this is important evidence.
Color photos of the injury should be taken.
http://www.nea.org/home/15453.htm