The district tells Action News a letter will went home to parents on Friday alerting them of the situation.
It says it will hold a free vaccination clinic on Monday at the high school for all Great Valley district families and staff who have not already been vaccinated.
You must be at least 11 years old to be vaccinated.
The students who came down with whopping cough are now being treated by a doctor.
Whooping cough is a highly contagious disease that is spread through the air.