Types of flu viruses

Scientists have classified influenza viruses into three types:

• Type A is the most common and usually causes the most serious epidemics.
• Type B outbreaks also can cause epidemics, but the disease it produces is generally milder than that caused by the previous type
• Type C viruses on the other hand, have never been connected with a large epidemic.

Incidence of the condition

Flu is a common illness. Every year in the United States, 5% to 20% of the population gets the flu; more than 200,000 people are hospitalized from flu complications, and; about 36,000 people die from it.

Flu vaccine

The bast way to prevent a flu is to get a yearly flu vaccine. It can be given almost everywhere: at a doctor's office, local clinic, and in many communities at workplaces, supermarkets, and drugstores. The problem with the vaccine is that you should get the vaccine every year because the virus is changing.

Why should you get a flu shot?

Many people think that they don’t need to get a flu shot because flu is not a serious infection. This isn’t so because, beside the fact that this infection really stresses the body,  there is also a danger of developing a superinfection which is very common. What exactly is a superinfection? It is a bacterial infection that occurs due to some respiratory infection. They could be very serious because having both viral and bacterial infection at the same time can overwhelm the lungs and the body and even cause death. 

Preparation of the vaccine 

Scientists make a different vaccine every year because the strains of flu viruses change constantly and each year different strains become dominant. That’s why, due to the very high mutability of the virus, a particular vaccine formulation usually only work for no longer than a year. About 9 to 10 months before the flu season begins, experts are preparing a new vaccine made from inactivated (killed) flu viruses. Since the viruses have been killed, they cannot cause infection. The vaccine preparation is based on the strains of the flu viruses that are in circulation at the time. This should be 100% effective. Sometimes however, an unpredicted new strain may appear after the vaccine has been made and distributed and that’s why, even if someone gets the flu vaccine, he or she may still get infected. 

Mechanism of work

What is the most important thing we should know about the mechanism of flu vaccination? Well, the flu shot contains killed flu viruses that will not cause the infection, but will cause body to fight off the infection by the live flu virus. This is because getting a shot of the killed virus causes body to protect itself against that particular type of live flu virus. The flu vaccine reduces the average person's chances of catching the flu by up to 80% during the season. Although there is still a possibility that person could get a flu even after vaccination, the good thing is that in this case the symptoms are usually milder.