What is the Influenza virus and how can we protect against it?

H1N1-influenzaOur body has the Immune System, which, among other things, protects it against infectious agents (Antigens). When an antigen comes in contact with our body for the first time, the immune system produces a series of antibodies to destroy it. For years, sometimes forever, this system “remembers” this particular infectious agent, and in a second meeting with it, it reacts faster and more intensely. That is what we know like “cellular memory”, and under these conditions it is said that our body is immune to this antigen.


This is the protection that it aims to get, although artificially, with the vaccines. A vaccine is a preparation of pathogenic agents (virus, bacteria…) that can be inactive or attenuated, which have lost the ability to cause infection, but they retain the ability to stimulate the immune response when they are introduced into our body. So, when we vaccinate for a disease, our body becomes immune to it for a variable period of time.


Next, we are going to address one of the viral infections that cause annual epidemics due to its constant mutability:  the Influenza, commonly known as “the flu”.

The flu is a disease caused by the influenza virus, which concerns the respiratory system. This microorganism has a great transmission capacity, as it may be passed on people easily through inhaling droplets of saliva from a person who has the virus when coughing, sneezing or talking. The main symptoms which it causes are headache, chills, high fever, dry cough, muscle and joint pain, malaise, fatigue and other respiratory symptoms.

This symptomatology generally begin to appear between the second and third day after contact with the virus (incubation period) and it may last from seven to ten days. According to World Health Organization (WHO), most of the people affected recover in one or two weeks without need to receive medical treatment. Nevertheless, in people with more risk, the influenza can cause a series of respiratory complications (like pneumonia) and even the death. This group with high risk includes:

-Children younger than two years of age.

– People over 65 years.

– And people of any ages, with certain illness like immunodeficiency or chronic cardiac, pulmonary, renal, hepatic, blood, and metabolic diseases.


antigripal20134To prevent the disease and its complications, the most effective form is the vaccine. The composition of the flu vaccine must be checked every year to modify it, because of the constant changes of this virus. For it, the Global Influenza Surveillance Network (GISN), a partnership of National Influenza Centres around the world, monitors the influenza viruses circulating in humans. Thus, the higher the concordance between the circulating viruses and vaccine viruses is, the more efficient the influenza vaccination will be. This year, this intramuscular vaccine protects against three types of flu: Influenza A (H1N1), Influenza A (H3N2) and Influenza B.

The Anti-Influenza vaccination campaign starts each autumn with the aim to reduce the morbidity and mortality associated with the flu, and the impact of the disease in the community.

Besides the groups at high risk mentioned above, vaccination is recommended primarily to all health-care staff (doctors, nurses…), pregnant women in any month of gestation, and workers of institutions like geriatric residences or chronic centres.


Finally, it is worth recalling that in addition to this prevention, hygienic measures are very important to avoid transmitting this kind of respiratory infection.


-Sources: World Health Organization, Medline Plus, Microbiología e Inmunología on-line

-Image: Vaccine, Virus

Author Spotlight

Patricia Delgado Delgado


Student of Nursing at the University of Granada (2010-present).

Writer of the Science section at We Learn Today. Read Full

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