During the winter there is a large increase in respiratory tract infections.

The reason for this increase is what is known as “increased viral circulation” because these tiny microorganisms find at this time of the year the ideal conditions to remain in the air and to spread from person to person through this medium. Similarly, it is also because the small speeds and mucous membranes of the nose are the natural defense system we have and when it is cold, they lose their movement, which prevents them from controlling the passage of microorganisms that penetrate the body more easily, unlike when it is hot.


What happens when infection overcomes our defenses?


Viruses, when they overcome the immunity mechanisms, adhere to the surface of the cells of the respiratory tract and penetrate the cell membranes, thus causing inflammatory processes that can culminate in cell death, but also with intense defensive processes that produce cell damage, increased secretions, local discomfort and irritative cough. Sometimes, if the defence processes do not work properly, more serious and complex infections can be caused by another type of microorganism, bacteria.


Most cases begin in the upper airway (nose, pharynx, larynx, middle ear) and can extend to the lower airway and affect the trachea, bronchi and occasionally the lung tissue itself, causing infectious conditions known as pneumonia.


We are all exposed to respiratory diseases, but it is more common in children and more because their immune system, which protects them, is not fully mature unlike an adult, also because of their age they live more with other children.


Another factor associated with respiratory illnesses during the winter is contamination inside the home due to lack of adequate ventilation. Usually, during the winter period, more time is spent indoors, this can cause a sick person or with the beginnings of a cold, infecting several people who are in the same space.


Other causes are sudden changes in temperature and not protecting yourself by covering your nose and mouth. It is common that in many public spaces there is heating, when going out, people are faced with a very drastic change in temperature, this decompensation can make it easier to get sick.


Several specialists have defined another factor as one of the main reasons why we get the flu during the cold season. found that influenza maintains its characteristic virulence in human mucus, but what allows it to survive better is ambient humidity below 50%. The typical conditions of any closed and heated winter home. The virus can proliferate if droplets of human mucus can evaporate and remain floating in the air, as they do under these conditions.


The flu virus also thrives in humidity above 98%, typical of rainy seasons in tropical areas. But in humidities between 50% and 98%, it becomes difficult for it to survive. It is somewhat rare to see flu in the middle of spring, less so in the summer, or in warm autumns when people do not use home heating, and these are also times when the humidity is usually between 50 and 70% in cities. But it is when the cold winter air is warmed and dried in the home that the virus does best to survive.


Ideally, you want to keep the humidity in your home between 50 and 60% to keep the flu away, and also to prevent excess moisture from creating mold on the walls. So if someone comes home with the flu, no matter how much they cough, the virus won’t survive in the air. While not the extreme solution, as flu transmission is still a puzzle, of which moisture may be just one piece.