Measles (rubeola) is an acute, highly contagious viral respiratory illness characterized by a distinct prodrome of fever and the "three Cs" (cough, coryza, and conjunctivitis), followed by a generalized rash. While indigenous transmission was declared eliminated in the U.S. in 2000, outbreaks continue to occur due to importation and unvaccinated populations.

Clinical Presentation and Transmission

• High Infectivity: The virus spreads via respiratory droplets and can remain airborne in closed areas for up to 2 hours. It is highly communicable, with a secondary attack rate of over 90% among susceptible contacts.

• Contagious Period: Patients are contagious from 4 days before until 4 days after the rash appears.

• Symptom Timeline: