11/01/2011 12:07 pm ET Updated Jan 01, 2012

Rihanna Hospitalized With The Flu; How Bad Is It?

It looks like Rihanna was the man down yesterday when she was forced to cancel her Halloween show in the Swedish city of Malmo due to exhaustion and a case of the flu, TMZ reports. The singer's symptoms got so bad she was hospitalized and treated with an IV, which she later tweeted a photo of, along with an apology to fans.

But can the flu really get that bad? The CDC says it depends. "Flu is unpredictable and how severe it is can vary widely from one season to the next depending on many things, including what flu viruses are spreading, how much flu vaccine is available, when vaccine is available, how many people get vaccinated and how well the flu vaccine is matched to flu viruses that are causing illness," the CDC says.

That means not all seasonal flu is created equal. Here are ten other myths you may not know about the flu, according to Harvard Medical School.

You can catch the flu from the vaccine.

The vaccine is made from an inactivated virus that can't transmit infection. So people who get sick after receiving a flu vaccination were going to get sick anyway. It takes a week or two to get protection from the vaccine. But people assume that because they got sick after getting the vaccine, the shot caused their illness.

Healthy people don't need to be vaccinated.
It's true that the flu vaccination is routinely recommended for people who have a chronic illness. But anyone — even healthy folks — can benefit from being vaccinated. Current guidelines suggest that children ages 6 months to 19 years old, pregnant women, and anyone over age 49 be vaccinated each year. In addition, the flu shot is recommended for healthy people who might spread the virus to others who are particularly susceptible. For this reason, health care workers are routinely advised to get the flu vaccination to protect their patients.

Getting the flu vaccination is all you need to do to protect yourself from the flu.
There are a number of steps you can take to protect yourself during flu season besides vaccination. Avoid contact with people who have the flu, wash your hands frequently, and consider taking anti-viral medications if you were exposed to the flu before being vaccinated.

The flu is just a bad cold.
Influenza may cause bad cold symptoms. But in the United States alone, 36,000 people die and more than 200,000 are hospitalized each year because of the flu.

You can't spread the flu if you're feeling well.
Actually, 20% to 30% of people carrying the influenza virus have no symptoms.

You don't need to get a flu shot every year.
The influenza virus changes (mutates) each year. So getting vaccinated each year is important to make sure you have immunity to the strains most likely to cause an outbreak.

You can catch the flu from going out in cold weather without a coat, with wet hair or by sitting near a drafty window
The only way to catch the flu is by being exposed to the influenza virus. Flu season coincides with the cold weather. So people often associate the flu with a cold, drafty environment. But, they are not related.

Feed a cold, starve a fever.
If you have the flu (or a cold) and a fever, you need more fluids. There's little reason to increase or decrease how much you eat. Though you may have no appetite, "starving" yourself will accomplish little. And poor nutrition will not help you get better.

Chicken soup will speed your recovery from the flu.
Hot liquids can soothe a sore throat and provide much needed fluids. But chicken soup has no other specific qualities that can help fight the flu.

If you have a high fever with the flu that lasts more than a day or two, antibiotics may be necessary.
Antibiotics work well against bacteria, but they aren't effective for a viral infection like the flu. Then again, some people develop a bacterial infection as a complication of the flu, so it may be a good idea to get checked out if your symptoms drag on or worsen.

Ready to put your flu facts to the test? Rate your knowledge with this 12-question quiz.