10 Surprisingly Believable Bits of Malarkey

Flu Shots Can Cause the Flu
Flu vaccines won't actually give you the flu. Tim Boyle/Getty Images

When (or if) you get a flu shot, the doctor, nurse or pharmacist probably offers a disclaimer that goes something like: After your shot, you may experience a low fever, aches or a runny nose for a few days.

So, it can cause the flu?

And anyone who knows just a little about how vaccines work knows that the flu virus is actually in the flu vaccine.

So, it can cause the flu?

Nope. The flu virus is injected into your body when you get a flu shot, but that virus is dead as a doornail [source: Today]. A dead virus can't infect anybody -- however, it can still stimulate your immune system to learn how to fight it, so if you come into contact with the live version, your defenses are already in place, ready and able (in most healthy individuals) to destroy it before it can put you in bed for a week.

The nasal-spray form of the vaccine does contain a live, significantly weakened form of the virus -- that kind is only used in healthy people, neither very young nor very old, whose immune systems are in top form. "Flulike symptoms" are more likely to develop with the nasal spray, but they fade once the immune system figures it out, and before it turns into the actual, awful flu [source: MedLine].

Next, a misperception that can lead to disaster.

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