Measles is making a comeback around the country due to declining vaccination rates, the Centers for Disease Control says. The past few years have represented the highest concentration of measles cases in America in more than three decades.

Measles is highly infectious to those who are not vaccinated, but it is extremely rare for a vaccinated individual to contract it, according to health officials. In the highly unlikely case a vaccinated person does get measles, they usually have milder symptoms.

Symptoms of measles include cold-like symptoms, runny nose, red eyes, greyish-white spots in the mouth, fever, and more. It’s transmitted most commonly through coughing and sneezing.Measles can remain infectious in the air and on surfaces for up to two hours after an infected individual leaves that area.

The MMR vaccine that provides full immunity is available at many healthcare provider offices and pharmacies.

If you develop symptoms, contact your health care provider immediately.