Influenza Vaccine

Brand names of influenza vaccine

  • Flu-Immune
  • Flumist
  • Fluoge
  • Flu-Shield
  • Fluzone

Immunization against influenza, also called flu shot, is basically a given with a view to protect an individual from the attacks of an extremely unpredictable influenza virus for a period of one year. This vaccination needs to be taken every year. It may be noted that influenza vaccinations for each season have three flu viruses one each - influenza virus strain belonging to type A, sub-type H3N2; influenza virus strain belonging to type B; and influenza virus strain belonging to type A and sub-type H1N1 (also called seasonal). In other words, the seasonal flu vaccination protects an individual against two A strains of influenza virus and one B strain of influenza virus. In March 2012, the Food and Drug Administration approved the use of quadrivalent influenza vaccine (seasonal flu vaccine), which is administered through the nose, whereas the use of Fluarix Quadrivalent was approved in December 2012 in the United States.

The usefulness of any flu shot largely depends on the degree to which the virus strains employed to make the vaccine match with one another as well as the specific viruses that are actually in circulation. In addition, an individual's age as well as health condition also have a major role in ascertaining the usefulness of the vaccine. Studies have revealed that an excellent match among the virus strains selected to prepare the vaccine as well as the viruses that are actually circulating, the vaccine can help to put off influenza ailment in roughly 70 per cent to 90 per cent adults who are healthy and below the age of 65 years.

A research involving children in the age group of 1 year to 15 years has demonstrated that flu shots rendered inactive was as useful as 77 per cent to 91 per cent in checking influenza respiratory ailment. However, the efficiency of vaccines in thwarting respiratory ailments in individuals above the age of 65 years is less to some extent. On the other hand, flu shots are very useful in putting off serious ailments, lesser complications and even death among elderly people undergoing treatment in nursing homes. Influenza vaccine may possibly be effective to the extent of anything between 50 per cent and 60 per cent in checking hospitalization owing to diseases related to influenza or pneumonia. It is also effective in preventing about 80 per cent deaths related to influenza. However, its usefulness in checking influenza respiratory ailment may possibly be very low, just about 30 per cent to 40 per cent.

Besides being an extremely contagious ailment, influenza is also a severe viral infection of the respiratory system. While the symptoms of other respiratory infections attributable to viruses are generally mild and majority of the patients are able to keep working or attending school even when they are ill, when you have influenza the symptoms are not only serious, but also continue for an extended period and force the patients to be absent from work as well as school for days together. Moreover, in such cases, the patients may also develop super-infections. Precisely speaking, super-infections are infections caused by bacteria that develop in addition to the infection of the respiratory tract by viruses.

Similar to viral infections of the respiratory system, those caused by bacteria are also very serious and when both these infections occur simultaneously, it may devastate the functioning of the lungs as well as the body. It may even result in death among people who are aged and little children. It is extremely essential to take the flu shot to prevent the occurrence of influenza, as this disease is not only extremely infectious, but also morbid (serious symptoms that prevent one from attending work and school), and has the potential to cause death. Apart from the flu shot, several medications that prevent the occurrence of influenza are available, but they are too costly, less useful compared to the vaccination, and require starting therapy within 24 hours to 48 hours of the onset of the symptoms.

On several occasions during their lifetime, individuals come in contact with dissimilar influenza virus strains. While the virus undergoes transformation, to some extent, the earlier attacks of influenza are likely to protect an individual against the contagion caused by any virus strain that is akin to those that invaded him/ her previously. Nevertheless, the influenza type A virus undergoes a drastic transformation about thrice or four times in every century giving rise to a new virus strain. The reason behind such radical change in the influenza A virus is yet to be ascertained by scientists.

Who should not receive the flu vaccine?

Although the influenza vaccine is extremely effective in protecting us from being affected by the strains of influenza virus, it should not be taken by individuals having specific health conditions, such as those who have allergies to eggs. However, individuals who suffer from minor allergies to eggs, wherein the reaction is only restricted to hives, may be administered TIV (trivalent inactivated influenza vaccine) with great caution. Before receiving TIV, you should ensure that you inform your healthcare provider or physician if you have allergic reactions to any substance.

Individuals who have suffered a serious allergy to a flu shot at any point in their life should not receive influenza vaccine again.

In addition, individuals who have suffered from Guillain- Barr� Syndrome (a serious paralytic ailment, which is also known as GBS) which might have developed following the administration of a flu shot and normally those who do not have any chance of developing any serious ailment from flu should not be administered this vaccine. In case you have suffered from Guillain- Barr� Syndrome in the past, you should notify your physician about it. In such cases, your physician will determine whether or not you should receive influenza vaccine.

People who are below the age of 65 years should not be administered influenza vaccine in high doses. Moreover, intradermal influenza vaccine should never be administered to people who are aged below 18 years or more than 64 years old.

Anyone who is suffering from moderate to serious ailments that may be accompanied with or with no fever ought to receive the flu shot only when they completely recuperate from their condition. When you are suffering from any ailment you should essentially consult your physician whether or not you need to reschedule your influenza vaccine. However, those who are suffering from any mild ailment can receive the flu shot.


Influenza vaccine is given to facilitate putting off infections caused by the flu viruses.

How influenza vaccine works

Influenza vaccine or flu shot is basically an injection that acts by establishing an inactive or dead influenza virus in our body. This inactivated flu virus encourages our immune system to make antibodies that help to protect us from the ailment. In fact, the virus that is introduced into our body in the form of a flu shot is the same as the one which the World Health Organization (WHO) is certain of appearing for the duration of the ensuing flu season, because the influenza virus strains transform not only every season, but also each year.

Side effects

  • reddened skin
  • hives
  • swollen face, eyes, or nasal passages
  • serious allergic reaction
  • unusual and severe fatigue
  • itching
  • redness, or hard lump at site of injection
  • pain
Less common

Possible interactions

Herbal medicines or minerals:
A number of patients suffering from influenza use the herb Echinacea with a view to perk up their immunity against different ailments. In other word, Echinacea is often used to perk up the immune system. However, it is really unfortunate that people who are suffering from an impaired immune system are not advised against using this herb. In effect, when Echinacea is used very frequently or for a prolonged period of time, it may result in the deterioration of the immune system.
Exposure to heat:
Administration of influenza vaccine may possibly result in developing fevers for a while. Therefore, it is prudent for people who have receive the flu shot to stay away from hot surroundings at least for one day after receiving the vaccination.
Heavy exercise or exertion:
Since you may develop a fever after being given the flu shot, it is advisable that you keep away from undertaking any rigorous exercise for at least one day after receiving the vaccination.

Storage instructions

Ideally, you should always store the influenza vaccine in a refrigerator. Provided you store the vaccine in this manner, it will remain valid till the expiry date printed by the manufacturer on the product. However, in case you store the flu shot at the usual temperature of your living room, the vaccine will remain usable only for a maximum of seven days.