Scientists are still working on exactly how we catch those colds. It’s a lot more complicated than you might expect!

“And don’t forget the boxes of tissues!” Mrs. Goldberg calls.

It’s the first day of school, and children all over the United States are streaming into their classrooms lugging backpacks full of notebooks, pencils — and boxes of tissues. Yet no matter how many boxes come in, by the middle of the winter, there’s not a tissue in sight. All that’s left are runny noses and uncontrollable sneezes.

That’s not surprising when you realize children suffer between six and ten colds per year, from September to May. If each cold lasts a week to ten days, that’s approximately 60 congested days every year! With an estimated one billion colds in the United States each winter, doctors should know everything about this common illness. There should be a vaccine changing winters from runny rounds of colds to a season of snowballs and sledding, right?

Wrong. While the cold is common, the solution is definitely not as close as the next tissue. Scientists are still working on exactly how we catch those colds. It’s a lot more complicated than you might expect!

Nose-It-All

During World War I (1914–1918), researchers believed that nasal secretions (mucus) from a sick person, placed on a healthy person’s nose or eyes, would automatically cause a cold. A handful of volunteers ran an experiment to test this out.

While many of the healthy people did get sick, around ten percent of the volunteers didn’t. Even stranger, one out of four tested sick, but had no symptoms — something called a “silent cold.” Were they missing something?

The invention of high-speed flash photographs in the 1940s led to the next theory. Viewing a high-speed photograph of a sneeze was like watching water shooting from a hose — thousands of droplets sprayed out of the subject’s mouth and nose at speeds close to 100 miles per hour! British scientists discovered that if a plate was placed three feet away from someone sneezing, 19,000 colonies (groups) of bacteria could reach it. Tiny particles from a sneeze could remain in the air long after the sneezer left the room.

Now scientists were sure: Colds spread through germ-filled drops in the air. But could they prove it?