Updated: Friday, 27 Jan 2012, 5:21 PM EST
Published : Friday, 27 Jan 2012, 11:53 AM EST
Health officials in Malvern, Pa., confirm to Fox 29 that whooping cough has been confirmed at Great Valley High School.
Whooping Cough, or Pertussis, is a highly contagious disease that causes uncontrollable, violent coughing.
Fox 29 has learned there were two cases at the school recently.
Many people are vaccinated against the disease, but those without inoculation face health risks.
Initial symptoms, similar to the common cold, usually develop about a week after exposure to the bacteria.
Severe episodes of coughing start about 10 to 12 days later.
The Natiional Institutes of Health says during a pertussis outbreak, unimmunized children under age 7 should not attend school or public gatherings, and should be isolated from anyone known or suspected to be infected. The period should last until 14 days after the last reported case.