Influenza is an acute infectious disease of the respiratory tract caused by influenza A or influenza B virus. Every year, millions of people get the flu. It usually causes a mild illness, but can be serious and even fatal for people considered at risk: people over 65 years of age, newborns and people with certain chronic diseases. For this reason, getting a flu vaccination every year is essential for certain people.
Annual vaccination is recommended for children, people over 65 years of age and people who are in direct contact with risk groups. In addition, it is vitally important to vaccinate people with diseases that can lead to complications, such as asthma, diabetes, kidney disease, immune system diseases, obesity. These diseases sometimes take time to appear. By means of a genetic test it is possible to know the predisposition to suffer some diseases related to complications in the vaccine. For these people it is also highly recommended to be vaccinated annually.
One of the characteristics of the flu is its high capacity of contagion from one person to another. Influenza appears, above all, in winter and in an epidemic way, that is to say, every year there is a season in which there can be a great activity and circulation of the influenza virus. It is a major health problem, as it can cause complications and sometimes even death. It is estimated to affect between 5 and 15% of the population.
Influenza virus A or B has a great capacity to undergo variations in the proteins essential for the virus’s infectious capacity, i.e. in the surface antigens. These variations imply the appearance of new influenza viruses each season. Therefore, the vaccine must be different to combat each “new” influenza virus.
Vaccines are preparations consisting of an agent similar to the disease-causing microorganism. When this attenuated part (but incapable of producing the disease) is introduced into an individual’s organism, the latter recognizes it as something foreign and creates antibodies against it. Thanks to immunological memory, when the individual comes into contact with the virus, his immune response will be much faster and more effective.
For influenza, a new vaccine is needed every season because the virus undergoes variations. One is antigenic drift, i.e. the accumulation of point mutations in the genes encoding surface proteins. This is the reason why a person can become ill with influenza on different occasions throughout his or her life, since the antibodies generated in the first influenza are not fully effective in protecting the body from subsequent infections. As a result, the flu vaccine is modified annually to adapt it to the strains believed to be circulating in each season.
Another variation that the influenza virus can undergo is when genetic exchange occurs between animal and human viruses, making these new viruses transmissible from one person to another. In this case, the new virus can lead to a pandemic, characterized by affecting people all over the world, such as influenza A, Spanish flu or Asian flu.
This is why vaccines are so important. If a virus unknown to the scientific population appears and there is still no vaccine, it can cause a pandemic, taking thousands of lives with it. In the case of influenza, although it suffers variations every year, these are very well studied and it is possible to predict what type of mutations will appear, producing a vaccine that will be effective.
In short, if you are in a risk group or the results of your genetic test have indicated that you have a greater genetic predisposition to suffer from certain diseases, it is advisable to get a flu vaccine every year. In this way you will avoid its appearance and the possible complications it may generate.