Influenza vaccine



The flu vaccine is available every year to protect adults and children from the risk of being affected by the flu and its complications (Video).

In healthy people, the flu heals spontaneously in about a week; however, it can be more serious in some categories of people at risk:

  • age 65 or older
  • women who are pregnant at the beginning of the epidemic season
  • children and adults in particular health conditions (chronic heart or respiratory diseases)
  • children and adults with diseases that result in decreased antibody production

Anyone belonging to these categories could develop even serious complications such as, for example, bronchitis and pneumonia and it is therefore important that they undergo the flu vaccination.

There are also some persistent (chronic) diseases that can increase the risk of complications if you are affected by the flu:

  • asthma
  • tumors
  • chronic obstructive pulmonary disease (COPD)
  • cystic fibrosis
  • diabetes
  • HIV / AIDS
  • kidney or liver disease
  • obesity

Effectiveness of the flu vaccine

The flu vaccine is the best protection available to date against influenza viruses (read the Hoax).

The flu is usually a disease that heals spontaneously without leaving any aftermath.However, serious, sometimes fatal, complications can occur in certain population groups (risk categories) such as elderly people, pregnant women and individuals with certain diseases.

Each year the viruses to be included in the vaccine are chosen from those identified in the previous season.

Scientific studies have shown that the vaccine helps prevent infection, even if it confers only partial protection if strains of influenza viruses other than those included in the vaccine also circulate.

The level of protection may vary among the population, so the share of people protected from influenza following vaccination will not be 100%.

However, in vaccinated people, if it occurs, the disease will develop less severely and last less.

The protection of the vaccine gradually decreases over time but, above all, influenza viruses have the characteristic of changing rapidly.

Each year, the viral strains that are most likely to circulate in the population causing the flu are identified.

For this reason, according to the indications of the World Health Organization (WHO), every year a new flu vaccine is produced against the new circulating virus strains.
Therefore, it is recommended that the categories of people at risk repeat the vaccination every year.

How the flu shot is made and how it works

Currently in Italy there are trivalent influenza vaccines (TIV) which contain 2 type A viruses (H1N1 and H3N2) and one type B virus and a quadrivalent vaccine which contains 2 type A viruses (H1N1 and H3N2) and 2 type A viruses. B (read the Bufala).

There are three types of flu viruses:

  • type A, the most virulent. It has the greatest capacity to transform itself and, therefore, not to be recognized by the antibodies produced by the organism of individuals infected or vaccinated in previous years.The H1N1 strain, responsible for the 2009 pandemic, is a type A virus and past pandemics have also been caused by type A viruses
  • type B, generally causes less severe disease and is responsible for small outbreaks. It infects children the most
  • type C, normally causes mild illness, similar to the common cold

For most flu vaccines the viruses are cultured in eggs, then before being used for the vaccine, they are inactivated (killed) and purified. For this reason the vaccine cannot cause the flu.

For people over the age of 65 and those with weakened immune defenses, a type of so-called vaccine is recommended. adjuvanted, i.e. containing an oily substance which enhances the immune response.

The vaccine is given by injection under the skin (intradermal), in the shoulder region (upper arm).

It stimulates the body to produce antibodies to the influenza virus without causing the disease to develop.

Antibodies are proteins that recognize and fight germs, including viruses.
Immunity is obtained 10-14 days after vaccination and remains active for a period of six to eight months, then tends to decrease.

For this reason, and because the strains in circulation can change, it is necessary to have a flu shot at the start of each new flu season.

If you come into contact with the flu virus after vaccination, the body's defense system will recognize it immediately and start producing antibodies.

When to get vaccinated

The period indicated for the flu vaccination, in the Italian climatic situation, is the autumn one, starting from mid-October until the end of December.

Considering that the protection develops after two weeks from the injection, it lasts for about six months and that the maximum circulation of the flu viruses is expected in the months of January and February, the best time to get vaccinated is from early November to late December.

Side effects of the flu shot

Normally, the flu shot does not cause undesirable effects (side effects), however serious ones are very rare. Disorders (symptoms) such as general malaise, mild temperature changes and mild muscle aches may appear, starting 6 to 12 hours after vaccination and lasting 1 or 2 days. The arm may be sore and there may be redness (erythema) and swelling where the injection was given.

The flu shot cannot cause illness as it does not contain active viruses.

If, after vaccination, flu symptoms occur it is likely that you have been affected by a cold, a para flu (infection caused by a virus other than the flu which, however, causes similar disorders) or that you have been infected by "flu before the vaccine took effect.

Severe allergic reactions to the flu shot are very rare.

Who does not have to get vaccinated

The flu vaccine should not be given to:

  • infants under six months (due to the lack of controlled clinical studies demonstrating the "harmlessness of the vaccine in these age groups)
  • people who have experienced a severe allergic reaction (anaphylaxis) after the administration of a previous dose or a severe allergic reaction (anaphylaxis) to a component of the vaccine.People allergic to eggs have a higher risk of reactions because the flu viruses contained in the vaccines are grown in the egg and, therefore, small amounts of egg protein may be present in the vaccine. There are currently low or no flu vaccines available. , egg protein
  • people who have moderate or severe acute illness, with or without fever, ongoing. In this case, vaccination must be postponed after recovery
  • history of Guillain Barrè syndrome

During an antibiotic treatment, however, it is possible to get vaccinated.

Where to find the vaccine

Anyone who decides to get vaccinated against seasonal flu can purchase the vaccine at pharmacies.

The vaccine is offered free of charge by contacting your primary care physician:

  • to people identified and classified at risk of severe complications and, at times, fatal (elderly, chronically ill, etc.)
  • to people not classified at risk who carry out activities of particular social importance (doctors, health workers, police, etc.)
  • to pregnant women in any trimester of pregnancy

In-depth link

Ministry of Health. Influence

Editor'S Choice 2022

Polychlorinated biphenyls (PCBs)

Polychlorinated biphenyls (PCBs)

The term polychlorinated biphenyls or polychlorinated biphenyls (PCBs) indicates a mixture of chlorinated hydrocarbons used since 1930 for various industrial purposes. The industrial production of PCBs was interrupted or drastically reduced between the 1970s and



Carbohydrates are substances formed by carbon and water and are mainly contained in foods of plant origin, mostly in cereals. They have a fundamental role in human nutrition as they represent the main source of energy