The SARS-CoV-2 virus (from the original Wuhan to the Omicron variant) "catches evenly", although the most affected populations are between 20 and 50 years old approximately because they are currently the most mobile, says Dr. Samuel Ponce de Leon, head of the University Commission for the Attention of the Coronavirus Emergency.

Since the virus is transmitted fundamentally "in air droplets" that we expel when talking, sneezing, coughing, and that remain floating in the form of aerosol in closed environments, once again the fundamental barrier to avoid infection is the correct use of masks. Whenever we are in closed or semi-closed environments (classrooms, offices, churches...) and even in congregations of people outdoors, it is necessary to wear a mask and keep a healthy distance.

It is necessary to have proper ventilation of the areas where we are working or teaching or performing our activities. It is also essential that people who develop symptoms of the disease or who suspect they have COVID-19 should voluntarily self-confirm. Until I have "full knowledge of what I am experiencing, I will be able to make a decision. Whether to discontinue isolation or quarantine. Or if I am going to have a test or if I am going to consult my doctor".

In public transport, "where coexistence is very intimate", to minimize the risk of infection, vehicle windows should be kept open and proper hygiene, especially hand hygiene should be maintained. In addition to wearing a properly fitted mouthpiece and, if possible, using two "perfectly sealed" mouthpieces. Do not take them off or take them by hand.

All masks are useful. From those that can be easily made at home to different types of mouthguards that can be purchased in pharmacies. Ideally, the mask has three layers of cotton fabric or the material used to make surgical masks, the blue ones, which have folds that fit very well. There are also masks with a higher filtration capacity. They are the N95: they have very high efficiency for the particle filter and they fit better and better.

Others fit in the back, towards the occipital part, with two very strong straps. They close completely and make the mouthpiece airtight. Always wear the mask up to the bridge of the nose and under the chin. Any mask is useful. It is better than nothing. But, insists the PUIS Coordinator, the best ones are those with three layers, with a perfect fit and hermetic seal.

In the case of a family member with suspected infection, with symptoms, or already infected with COVID-19, in addition to self-confinement, food utensils should be washed "with soap and water and that's it".  No "other care" is necessary. Transmission of the virus, Ponce de León insists, is by air. Not through contact with such utensils (if they are washed) or food consumption.

One can become infected if after touching a surface (hand, glass, bottle...) where respiratory secretions have been deposited by coughing or sneezing on them, one grabs one's nose, eyes, or mouth. Currently, most infections are by Omicron and all variants of SARS-CoV-2 should be feared and precautions should be taken to avoid infection.

No one can guarantee that the evolution of an Omicron infection will be mild. Last week, a young man aged 30 years with his vaccinations suffered from severe respiratory failure due to the Omicron variant. We cannot because the virus is said to be less virulent, "be negligent or complacent with the precautions we have been taking so far".