Fact or Myth? You can catch the flu from a flu shot.
Answer: Myth
"That's the biggest myth, that's really huge. And it inhibits many people from thinking about getting their influenza injection," said Schaffner.
The idea rises from the popular misconception that the flu vaccine shot is a weakened form of the flu virus. The flu vaccine contains components of the flu virus but not a complete virus.
"There's no way that the shot can give you a complete influenza virus that can then make you ill," Schaffner said.
The reason many might believe that the vaccine can cause the flu, said Schaffner, is that people tend to get the flu vaccine in October or November, and then catch a cold from someone else.
Since the viruses that cause cold are contagious 24 hours before the symptoms appear, someone who had a flu shot and then caught a cold might believe he or she has the flu and can't think of another source because the person whom they got it from didn't appear sick.
Of course, in recent years, another form of the flu vaccine -- a nasal spray known as FluMist -- has also become popular.
The nasal spray, Schaffner explains, is a "tamed virus." In this case, it has been engineered to multiply in the nose, but it can't get down into the rest of the body because the rest of the body is a degree or two warmer than the nose, and the virus is incapable of multiplying at that higher temperature.
"It's a miracle of modern science," he said.
However, the nasal spray form of the flu vaccine may leave someone symptomatic for a day with a runny nose and a sore throat.
"That's a small price to pay, in my opinion," said Schaffner.
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