PLANO, Texas (CBSDFW.COM) – It’s the second week of school and there’s already a confirmed case of measles at Plano West Senior High School.

The time period when students, faculty and staff could have been exposed is August 14-16 according to Collin County Health Care Services.

The health agency sent the following health advisory to parents on Thursday:

“We would like to notify the school community that there has been one (1) confirmed case of measles at Plano West Senior High School. We are currently reviewing individual exposure status, although anyone at the school between August 14 – 16, 2018 could have had exposure to the case.

Measles is highly contagious and is transmitted primarily from person to person by respiratory droplets and airborne spread. Patients are contagious from four days before onset of rash to four days after appearance of rash. Symptoms of measles include rash, fever≥101°F, cough, runny nose, or eye redness. Any person suspected of having measles should contact their health care provider and stay at home until four days after rash onset has passed.

Measles contacts, even vaccinated contacts, should monitor themselves for measles symptoms until September 6, 2018. Contacts should be instructed to isolate themselves immediately if measles symptoms develop and notify the health department.

Those with weakened immune systems and children/staff members who are unvaccinated are at higher risk of complications from measles. Susceptible, unimmunized persons and partially immunized persons (i.e. persons who had received only one prior dose of MMR) who continue to refuse the recommended measles vaccination(s) following exposure to measles are asked to stay home from school, child care settings, and group settings until 21 days from last date of exposure. Their healthcare providers should be notified as soon as possible that they were exposed to measles.

All staff that cannot provide adequate evidence of immunity should be vaccinated, regardless of exposure status. A first dose should be given to those who are unvaccinated. Recommend a second MMR to persons who have previously received only one MMR as long as 28 days have passed since the first dose.

If you experience or have experienced measles symptoms, or if you have questions, please contact your healthcare provider immediately. Measles is a very contagious airborne disease. If you develop symptoms and decide you want to be seen at your doctor’s office or at a healthcare facility such as an emergency department or emergency clinic, PLEASE CALL THEM FIRST and inform them you were possibly exposed to measles. Please take this letter with you, so you will be properly evaluated upon arrival. If you have any questions please contact our office at 972-548-4707.

Collin County Health Care Services will continue to provide updates as needed.”

Texas is one of 18 states that allows parents to opt out of school immunizations and a new study shows Tarrant County and Collin County as “hot spots” for opting out.