Measles spreads mainly through the air from an infected person who coughs or sneezes, by breathing in droplets or by touching contaminated surfaces and then touching the eyes, nose, or mouth. It is one of the most contagious diseases and can remain airborne or on surfaces for several hours, so transmission can occur even after the infected person has left the area. People who are not immune are at high risk, and contagiousness begins a few days before symptoms appear and continues for several days after the rash develops. Key points
- Transmission routes: respiratory droplets from coughing or sneezing, and contact with contaminated surfaces; the virus can linger in the air for up to about two hours.
- Contagious window: typically from about four days before to four days after the appearance of the rash.
- Infectiousness: close contacts who are not immune have a very high risk of infection; up to roughly 90% of nonimmune close contacts can become infected in crowded settings.
- Susceptible populations: unvaccinated individuals, people with incomplete vaccination, infants, pregnant people, and those with weakened immune systems.
Practical guidance
- Vaccination: ensure you and your family are up to date with measles-containing vaccines (MMR or MMRV for children and adults as recommended). Vaccination is the most effective prevention.
- If exposed: contact a healthcare provider promptly to discuss post-exposure actions, which may include vaccination within a specific time window or other precautions.
- Infection control: in medical or school settings, rely on appropriate isolation for suspected cases and maintain proper ventilation and hygiene.
If you’d like, I can tailor this to a specific setting (school, workplace, or travel) or provide a brief FAQ for parents or educators.
