Clinic24 Hour RuleStudents who demonstrate signs and symptoms of illness or a possible communicable disease should be referred to the school clinic for further assessment. Those with an elevated temperature of 100.4 degrees or above or those who vomit or have diarrhea must be isolated and sent home. The students must be fever free without fever-reducing medication for 24 hours before he/she can be allowed back in school. Those excluded due to vomiting or diarrhea must also be free of symptoms without the use of preventative medications before being allowed back in school. (Administrative Regulation FFAD) The 24 hour period is used as the standard length of time to determine if indeed symptoms have subsided.ImmunizationsImmunization requirements and forms can be found on the Katy ISD Health Service Site.