Measles is transmitted mainly through the air and via droplets released when an infected person coughs, sneezes, or talks. It can linger in the air and on surfaces, so people can become infected by breathing contaminated air or by touching a surface or object and then touching the eyes, nose, or mouth. People are most contagious from several days before to several days after the appearance of the rash, and infection can occur even if the infected person does not have a fever yet or noticeable symptoms. Key points:

• Primary mode: airborne transmission through respiratory droplets and aerosolized particles.
• Infectious period: typically from about 4 days before to 4 days after the rash appears.
• High contagiousness: a susceptible person exposed to an infected individual has a high risk of becoming infected, particularly in indoor, crowded settings.
• Surfaces: measles virus can remain viable in the air for up to around 2 hours in an enclosed space after an infected person leaves.
• Immunity: vaccination (measles-containing vaccine) provides strong protection; unvaccinated individuals are at higher risk after exposure.

Practical implications:

• Vaccination is the best prevention; ensure up-to-date MMR (measles, mumps, rubella) vaccination for all eligible individuals.
• In outbreak or exposure situations, public health guidance may include post-exposure vaccination or immunoglobulin for those at risk, and isolation of confirmed cases.
• If exposure is suspected, contact a healthcare provider promptly, especially for unvaccinated or immunocompromised individuals.

If you’d like, I can tailor this to a specific setting (home, school, workplace) and provide a concise prevention checklist.