Got the sniffles? A fever? Body aches? You may be thinking flu but it's much more likely that you're just suffering from a cold, albeit a bad one. 

According to a new study published in the journal PLoS Biology, the flu is much less common than many people realize. It doesn't help that many people use the term "flu" to label everything from colds to allergies to an upset stomach.

The research team from the Imperial College of London found that the average adult only contracts the flu about twice every decade. "For adults, we found that influenza infection is actually much less common than some people think," said senior author Dr. Steven Riley.

They came to this conclusion after analyzing blood samples from volunteers in southern China to evaluate their levels of antibodies against nine different flu strains that circulated there between 1968 and 2009. The researchers found that, on average, children get the flu every other year, but flu infections become less frequent as people get into their 20s and 30s. After age 30, people tend to get the flu about every five years.

Children are considered "super-spreaders" of the flu because they mix with more people more often and also may be less diligent about things like hand washing and covering their mouths when they cough. They also have not yet built up an immunity to many flu strains simply because they haven't been exposed to them.

"What we've done in this study is to analyze how a person's immunity builds up over a lifetime of flu infections," said Adam Kucharski, another of the study's authors. "This information helps us understand the susceptibility of the population as a whole and how easy it is for new seasonal strains to spread through the population."

So the next time you're feeling lousy, rest assured that it's much more likely that you have a bad respiratory infection than the flu. That's not to say you don't feel sick, but if you grab some hot tea and catch some zzz's, you will probably be back on your feet in no time.

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