The flu vaccine: Is it miracle drug, or a cause for concern? Influenza, the formal name for the flu, is a contagious respiratory virus that infects up to 20-percent of the U.S. population each year. While some people recover from the flu quickly, others can stay sick for weeks, and each year 36,000 people die from the virus. Because different forms of the flu circulate each year, a new flu vaccine is developed annually. Each year's vaccine is designed to protect against the strains of the flu that are expected to circulate during that season. There are two different types of vaccine used.The more commonly used form contains inactivated, or dead, forms of the flu virus, and is delivered via an injection called the flu shot. Because the virus in the flu shot is dead, it cannot cause the flu in people who receive it, but it will help the body create antibodies to fight live flu viruses. The flu shot doesn't usually come with any side effects, although some people experience tenderness at the injection site. The flu vaccine is also available as a nasal spray, which contains live, but weakened versions of the flu virus. As a result, the nasal spray can cause flu-like symptoms in some individuals, although it cannot actually give you the flu,These symptoms-which may include headache, runny nose, and a sore throat-do not last for more than a day or two. Whichever kind of flu vaccine you choose, though, the CDC has developed a few guidelines to help you stay safe. One such recommendation is that you get the vaccine in September or November, before peak flu season starts. This is because the vaccine takes two weeks to create antibodies against the flu virus, and become effective. Because the nasal spray is more potent than the shot, this form is only recommended for healthy individuals between the ages of two and 49. Babies, people over 49, and thos with compromised immune systems, should stick with the flu shot.Of course, not everyone needs an annual flu vaccine. Only members of the following groups should always get one....pregnant women, children from six-months to 19 years old, adults over 50, people living in nursing homes, and people with certain medical conditions, like HIV. But even if you're not in a "recommended" group, it can still be smart to get the flu vaccine. After all, the vaccination protects against the flu about 80-percent of the time, and it's the most effective way to ward off the virus. So if you are someone who frequently comes into contact with children, like a teacher or a parent, or if you live in communal housing like a dorm or a sorority house, getting a flu shot is often a wise precaution. So why let germs defeat you? Fight back against the flu this season!