How Measles Spreads
By 22 October 2026 the United States had confirmed 4,588 measles cases, about twice as many as in all of 2025, and in November the Pan American Health Organization reviews whether the country still counts as measles-free. This film explains the fundamentals: a virus that floats in a room for up to two hours and spreads before anyone knows they are ill; the fever, spots and rash, and the complications that put about one in five unvaccinated patients in hospital; the “immune amnesia” that wipes out part of the body’s memory of other germs; the reproduction number and why about 95% coverage is the line that stops outbreaks; the vaccine, from the 1954 lab to the MMR shot; and what “elimination” means, how Canada lost it in 2025, and what an outbreak in southern Thailand in 2018 showed. Health education, not medical advice.
The virus that waits in the air
Why measles spreads so easily, and what stops it.
A virus in the air
Small, fragile, and very good at travelling.
The illness
A fever, spots in the mouth, then the rash.
Immune amnesia
A virus that makes the body forget.
The arithmetic of spread
One number decides how fast it grows.
A vaccine
From one sick schoolboy to MMR.
Keeping it out
An average can hide a gap; elimination can be lost.
Read the full story as text · อ่านภาษาไทย
This interactive 3D film needs JavaScript. PlanetPast home