Major US airport on red alert as passenger is diagnosed with world’s most infectious disease

Why Measles Is So Dangerous

Measles is often described as “the world’s most infectious disease”—and for good reason. The virus spreads through the air when an infected person coughs or sneezes, and it can linger in the environment for up to two hours after they leave.

This means you don’t even need direct contact with an infected person to catch it. Simply being in the same space—like an airport terminal—can be enough.

Common symptoms include:

• High fever
• Persistent cough
• Runny nose
• Red, watery eyes
• A distinctive rash that spreads across the body

In severe cases, measles can lead to complications such as pneumonia, brain swelling, and even death—especially in young children or unvaccinated individuals.