What are the arguments you hear most often from people who don't wanna get immunized against influenza? Is that "the flu just isn't that big a deal, I mean isn't it just a bad cold?" Really? The flu shot is the topic of this week's Health Care Triage.

Opening Sequence

Look, there are a number of things the flu and a cold have in common. They both involve a respiratory system, and they both include a cough and a runny or stuffy nose, and of course they both make you feel sick! But that's where the similarities end.

Colds are caused by a variety of viruses, mostly rhinoviruses (30-50%) and coronaviruses (10-15%). The flu on the other hand, is caused only by the influenza virus. Cold are defined as a short and mild illness first characterized by headache, sneezing, chills, and sore throat; later on you get runny or stuff nose, cough and you feel a little crabby.

Usually things move fast and colds are at their worst two to three days after infection. Most people start to feel better in a week to ten days after the cold starts. But some symptoms can last for weeks. Very few people with colds develop fevers.

Influenza, on the other hand, feels more like getting hit by a truck. Influenza also comes on fast, with more symptoms, like fever, cough, sore throat, headache, muscle pain, stuffy nose, weakness, and even a loss of appetite. You're likely to feel much much worse with the flu.

A lot of people think of the flu, or influenza, as stomach flu. While you might have a loss of appetite or an upset stomach, the main effect from the influenza is to make you achy, weak, and tired, with a bad cough, fever, and congestion.

Colds rarely do much more then annoy us and slow us down. I don't mean to minimize how bad you feel when you have a cold, but you can be pretty sure as to how bad it will get. Flu, on the other hand, can kill. In fact, the flu kills up to 500,000 people around the world each year. The number of people who die from colds is almost zero.

While there's no cure for the cold, there actually are antiviral medications that can help the flu to go away faster. In order for these medications to work, you need to start taking them in the first day or two after you get sick. That's why it's important to talk to your doctor as soon as possible after you feel sick in flu season.

Once those first few days have passed, the medications really won't do you any good. Although it's difficult to tell a flu from a cols at the beginning, the best predictors are cough and fever; having both of these symptoms has a positive predictive value of 80% in differentiating one from the other. So if you have a cough and a fever during flu season, there's a pretty darn good chance you've got influenza.

Most importantly, there's a vaccine for the flu. The flu shot works; it prevents illness and it saves lives. To the research! One recent study showed that from 2010 to 2012 kids who got the flu shot had a 74 percent lower risk of being admitted to a pediatric intensive care unit during flu season. Another showed that getting the vaccine was associated with a 71 percent reduction in adult flu-related hospitalizations, 77 percent in people fifty and above!

Studies show it's associated with the 79 percent reduction of hospitalization for people with diabetes, 52 percent reduction in people with chronic lung disease. Giving the vaccine to pregnant women is 92 percent effective for preventing hospitalizations of infants with the flu.

Yes, the flu vaccine changes from year to year and it's based on a best guess as to what strains will be most prevalent this season. Some years they do a better job predicting than others, but research shows consistently that the benefits outweigh any potential harm. The CDC currently recommends that every single person six months of age or older should get the flu shot. That includes pregnant women and people with lots of chronic illnesses.

There are some people who shouldn't get flu shots. If you have an allergy to chicken's eggs, if you've had a serious allergic reaction to a previous flu shot, if you have had the rare condition Guillain-Barre syndrome after a previous flu shot or if you have a moderate or severe illness with a fever at the time you want the shot, you probably shouldn't be vaccinated and you should at least talk to your doctor about it. Otherwise, recommendations say that you should get it.

Some people may tell you that the flu vaccine can give you the flu. It can't; the flu shot uses the dead viruses to protect you from influenza. Dead viruses can't make you sick. Dead viruses can't be resurrected to cause infections; they're dead. I know there's likely someone out there who is arguing with the video right now. maybe someone who thinks the flu shot gave them the flu in the past but it didn't happen. If you've ever thought that the flu shot gave you the flu, you might have experienced the side effect from the vaccine. Vaccines can cause soreness, redness, and swelling where you get the shot. Some people also experience some low-grade fever and aches. That's not the flu; that's just the lousy part of getting a shot, even though it's potentially saving your life. It's also possible you might have gotten sick right after the flu shot just by coincidence; maybe you were exposed to another virus around that time or even to influenza itself before you got the shot. When you get a shot and get sick at the same time, it's normal to put two and two together and assume that one caused the other. But once again, there's a difference between causation and association. Even if they happened at the same time, one event did not necessarily cause the other.

Now the nasal spray influenza vaccine doesn't have a dead virus; it has a live attenuated virus. But this live attenuated virus is a special genetically modified version of the influenza virus specifically designed not to cause infection. It doesn't revert back to the original virus that can cause infection. It's never happened, not is scientific studies, nor in the millions of people who have gotten the influenza nasal spray vaccine since 2003. Still, some people worry that the nasal spray version of the influenza vaccine can come out of your nose and be transmitted to someone else. Shedding of the vaccine from the nose can occur, but the amount of the vaccine virus that comes outta there is incredibly small, much less than you would need to infect someone else and, in the many many studies that have been done, transmission of this attenuated vaccine virus has only been seen in one person as far as I can tell by looking at the medical literature. Once child in a study of 197 children had influenza from someone else's vaccine detected in their nose in a single day but it never caused any symptoms. In all the other studies, no one transmitted the vaccine virus at all. Even among HIV-infected children and adults, who would be at a higher risk for infection, no one was infected. Of course, you should still wash your hands and try to stay away from close contact with sick people to avoid both the cold and the flu, but the vaccine can make a big difference. As I said a few weeks ago here on Healthcare Triage, it's estimated that, just two years ago, if we had just gotten the influenza vaccination rate up to 70%, we could have prevented 4.4 million illnesses and 30,000 hospitalizations in the United States alone. There's a reason the CDC recommends this vaccine for everyone; listen to them.