Why you sometimes feel a cold coming on, only to have the symptoms disappear the very next day.
The 24-hour cold. I’m Bob Hirshon and this is Science Update.
Have you ever felt like you were starting to come down with a cold, only to have it fizzle out within 24 hours? Infectious disease specialist William Schaffner of Vanderbilt University School of Medicine says one reason is that there’s a variety of cold viruses.
The number of viruses that can cause the common cold are greater than 100. Some are more aggressive—produce worse colds—than others.
Not only that, but if we’ve encountered a particular cold virus before, our immune system is primed to deal with it.
I might have seen that same cold virus ten years ago, so my body remembers that virus and quickly asserts itself and forces it down and recovers. But if we find a new one, then that can still give us a bad cold, even if though we’re 60 years of age and have seen a lot of colds in the past.
I’m Bob Hirshon, for AAAS, the science society.
Making Sense of the Research
Have you ever wondered why you can get a vaccine for the flu virus but not for the cold virus? The answer lies in the fact that there are nearly 250 different varieties of viruses that can cause the symptons of a cold, like the rhinovirus or the coronavirus, each of which has many subsets with a lot of variability. The flu, on the other hand, is caused just by the influenza virus, which makes it easier for scientists to develop vaccines for it.
You can catch a cold by coming into contact with another person who has a cold or simply touching a surface that has been infected with the virus and then touching your mouth or nose. You also can catch it if you're near someone who is sick and sneezes into the air.
If the virus does manage to enter into your body, it attaches to the lining of your nose or throat. Your body will respond by sending white blood cells to try to get rid of the virus. If you haven't had the particular strain of the cold virus before, the initial attack will fail but your body will send in some reinforcements. Your nose and throat will get inflamed and make a lot of mucous, which of course can make your nose stuffy and cause a cough.
Your body, though, has some natural defenses that help keep you from getting sick. The first line of defense your body has is your skin. If you keep your hands clean by washing them after you've come into contact with germy surfaces, you can help yourself from getting the cold. The mucous membranes around your eyes and nose also help to keep viruses from entering your body. And if the virus does get past these defenses, your immune system goes to work. If you've already had the virus before, your immune system can prevent you from getting it again or, as is the case explained in the story you listened to, you may only display mild symptons that will go away quickly.
Now try and answer these questions:
- Approximately how many cold viruses are there?
- How can you catch a cold?
- What steps does your body take to defend itself from the virus?
- What things can you do to try to keep yourself from getting sick?
- How does your immune system respond to a cold virus?
You can learn more about germs and viruses by listening to the Germy Surfaces Science Update.
You can help your students extend the ideas in this Science Update by watching the Does Being Cold Make You Sick? video. This video looks at whether or not you can get sick just from being out in the cold.