Measles, a highly contagious disease caused by the measles virus, primarily occurs during the winter and spring seasons. Individuals who have not received the measles vaccine have a more than 90% chance of contracting the disease after exposure, with the highest incidence among children aged 1-5 years.

Infected individuals are the sole source of transmission, as the measles virus can be found in their ocular, nasal, oral, and pharyngeal secretions (such as tears, nasal discharge, sputum) as well as urine and blood.

The incubation period of measles is 10-11 days. Initially, symptoms resemble those of a common cold but progress to more severe symptoms such as red eyes, swollen eyelids, tearing, sensitivity to light, sneezing, and coughing. The most common complication of measles is bronchopneumonia, which occurs in approximately 10% of cases. Other complications include laryngitis, otitis media, and encephalitis.

Measles is highly susceptible in the general population, particularly among infants and young children. However, in recent years, the age of onset has shifted due to widespread measles vaccination. Although childhood vaccination provides long-term immunity, antibody titers may gradually decrease over time, necessitating booster vaccinations to enhance immunity. Additionally, some individuals may not achieve 100% seroconversion after initial measles vaccination, and the immune response weakens over time, further highlighting the importance of supplemental immunization with measles vaccine.

Key preventive measures against measles include minimizing contact with patients and their family members, practicing good hygiene, timely administration of the measles vaccine, ensuring indoor air circulation, reducing visits to public places during peak seasons, engaging in physical exercise, and strengthening the body's resistance to disease.