Vaccination is only effective against the strains of influenza virus, to combat which they were created. That is why people each year require re-vaccination against influenza.

The benefits of vaccination against influenza

Influenza - a viral infection that is transmitted from person to person by airborne droplets, and develops mainly in the lungs. Usually, it causes fever, general malaise, severe body aches. Other viruses can also cause these symptoms, but it happens rarely. Influenza viruses are divided into three types - A, B and C. Influenza viruses A and B cause epidemics of respiratory diseases that occur almost every winter. Influenza virus usually leads to the development of a poorly defined respiratory disease, or do not cause any symptoms at all; they do not cause epidemics or, respectively, vaccinations are usually do not. Every year, flu sick much of the population - from 5% to 20%; Only in the US each year 200,000 people infected with the flu are hospitalized and about 36,000 people die from influenza and its complications.

Influenza is a highly contagious and potentially dangerous disease .  If infection by other viral respiratory infections, many people feel quite normal, and even continue to work and learn, because of the human influenza may temporarily lose the ability to work virtually .  This disease is a serious stress for the body .  In some cases, the flu can lead to superinfection - this infection, the infection which occurs soon after infection of primary infection .  Activators superinfection may be not only viruses and bacteria; simultaneously occurring viral and bacterial infections can lead to serious problems in the lungs, and in the elderly, they sometimes lead to death .  Thus, flu shots are needed for several reasons: because of its contagious, because he is poorly tolerated, even in otherwise healthy people, as well as due to the fact that it can lead to serious complications and even death .  Although drugs exist to treat influenza, they are quite expensive, are less effective than the vaccine and need to start taking 24-48 hours after the first symptoms .

Types of influenza vaccines

At present, each year are immunized against seasonal influenza, but in some cases can be developed and pandemic vaccines, as was the case in 2009, when the planet began to spread the flu virus H1N1.

Most often there are two types of vaccines for seasonal flu: injectable vaccine (containing dead virus) vaccine and as a nasal spray (they contain a live, but weakened virus). In 2011, for the first time used a new type of vaccine - they are administered intradermally (in the skin) rather than intramuscular injection, as was done until now. However, and now most frequently used vaccine for intramuscular administration.

Each year, the flu virus is changing, which is why the vaccine, which was used in the last year, become ineffective. Therefore, every year, a new vaccine, which will be an effective tool against the new influenza virus. The reason for the constant changes in the virus lies in the fact that the virus can mutate quickly, but in most cases, scientists can determine in advance how it will be a mutation, and therefore, to develop a vaccine against the mutated virus.

Viruses, which are used for making flu vaccines, typically grown in chicken eggs Chicken eggs: a universal and irreplaceable product But recently began to appear new vaccines for viruses that have been grown in a different environment. This is especially important for people who are allergic to eggs.

Injectable flu vaccine refers to an inactivated vaccine because it, as already mentioned, contains dead flu virus. When the virus is administered into the muscle or into the skin, the immune system produces antibodies to the influenza virus. Thus, there is a means of protecting the body against the virus in case it is again "meet" with him.

The flu season in 2014 will use two main types of influenza vaccination: trivalent vaccine, which is effective against three strains of influenza virus, and the quadrivalent vaccine - to deal with four different strains. In addition, special vaccines are available for people over 65 years old - they provide greater protection against the flu, and are optimal for this group of patients because their immune system is often weakened.

Nasal flu vaccine was first used in 2003. Because this vaccine contains a weakened but live virus, it is not recommended:

• Patients under the age of two years;
• Patients over fifty years;
• People who have diseases associated with an increased risk of complications from influenza, such as - chronic heart disease Heart disease - symptoms of heart disease   and lung;
• Patients with diabetes or renal failure;
• Patients with diseases that weaken the immune system, or taking medications that weaken the immune system;
• People taking aspirin;
• pregnant women;
• People who are allergic to chicken eggs or to any component of the vaccine;
• Patients with Guillain-Barre syndrome.

In healthy people, the vaccine can cause mild side effects, such as mild runny nose, headache, sore throat and cough. In children, after applying the nasal vaccine may slightly raise the body temperature, muscle pain sometimes appear. However, these side effects are normally pass quickly; if they persist for several days, you should consult your doctor.

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