Irene Fernández

Chronology of a covid infection with the new variants: what happens day by day in our body

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  • We explain how the virus infects us and what happens in the body from that moment: the process varies according to the different variants


  • In the current covid, generated by omicron BA.4 or BA.5, the symptoms start earlier and last longer, but are milder


  • The infected are becoming contagious earlier: with each variant, the chain of transmission accelerates

The SARS-CoV-2 with which we are infected now has little to do with the virus that infected us at the beginning of the pandemic. It is the same, yes, but it has incorporated many changes, both in the way we get infected and in the immunity that this infection generates. From the original variant of the virus, the one that came from Wuhan, we go to alpha. From alpha we go to delta. And from delta, to omicron, which is the current variant. But with the latter, the virus is evolving so much and so fast that some subvariants of omicron, such as BA.4 or BA.5, incorporate important mutations. The symptoms of the current covid are different, they arrive earlier and last longer. But the infection process is also different. How does the virus infect us now? How do these new variants interact with our body? We explain what happens every day, since we come into contact with the pathogen.

Day 0: infection

We become infected when we have close contact with someone with covid. How? Mainly, by inhaling the aerosols exhaled by that person when they speak, cough, sneeze or simply breathe. Because they are infective aerosols.

Days 1, 2 and 3: incubation

Once the virus invades our cells, it begins its task of dispersing as much as possible through our body. But, at first, he does it quietly. Since we got infected a few days pass until the symptoms appear, which takes our immune system to react to defend. The symptoms are that defensive reaction.

During those days of silent incubation, you can be contagious. And, in fact, they are the most dangerous, because having no symptoms, we are not aware that we are infected, that we have the virus in our body. We live a normal life and we spread it very easily.

But this incubation period has been shortening with each variant:

With alpha: six days until symptoms

With delta: four days until symptoms

With omicron and its subvariants: three days until symptoms

Why are these new subvariants more contagious, then? Among other things, because they infect our cells faster than the previous ones. In addition to better evade the immune system.

It should be noted in this connection that being infected is not the same as being contagious. Before, there was more time between the two moments, but that time has also been reduced with each variant: the infected each time infect earlier. With omicron, before with delta. With BA.4 and BA.5, even more. With each variant, the transmission chain speeds up.

It has also been proven that BA.4 and BA.5 are transmitted with very low viral loadsbefore they can even be detected by antigen tests. That is why we are seeing people who continue to test negative and yet are contagious.

Days 4 to 14: evolution of symptoms

Both the original omicron and its currently dominant subvariants, BA.4 and BA.5, cause a milder infection than the previous ones. Because it affects, above all, the upper respiratory tract (throat, nose and mouth). This does not help, in the face of contagion, since these infections do not force you to stay at home or in bed. But how long do they last?

The BA.4 and BA.5 symptoms are more durable. They keep an average of about seven days, three days longer than the original version of ómicron, BA.1, lasted. Although they are also lighter. But all this is the average, the evolution of the infection depends on each person, on his immune system.

Usually, The symptoms that will appear during these days are:

  • Asthenia or fatigue, which affects 75% of cases
  • Cough (58%)
  • Fever (58%)
  • Headache (52%)
  • Runny nose (50%)

To a lesser extent, although more frequently than before, there may also be:

  • Muscle pain
  • throat pain
  • difficulty breathing
  • dizziness

The most bothersome symptoms, such as fever, usually disappear sooner. The milder ones, such as cough or runny nose, persist longer.

Day 15 and later: end of infection (or not)

Usually, Two weeks after infection, the immune system usually wins the battle against the virus. The symptoms disappear and our body recovers. Unless the virus has managed to reach vital organs and cause significant damage, which requires hospitalization and, in some cases, can lead to death. The objective of the vaccines is precisely to prevent us from reaching that point. And in the vast majority of cases they are succeeding.

The The problem is when, after a while, some of these symptoms do not go away. How long? Three months. From that moment on, it is considered that there may be a problem if one or more of the symptoms generated by covid persist, or new ones appear, after having overcome the disease. Symptoms of the most diverse that can last for months. Or years. It’s impossible to know yetbecause being a new virus, not enough time has passed.

In In Spain, it is estimated that there are one million people affected by the so-called “persistent covid”. In the world, one hundred million. And there is no specific treatment, despite the fact that it is already “officially” recognized as a disease by the WHO. All approaches focus on alleviating symptoms.

And the symptoms that are seen are the most non-specific. from asthenia, dyspnea or tachycardia even burning hands and feet, hypersensitivity in the teeth or aphonia. Some more, some less, all condition the life of the one who suffers them. A large part of them are people who were infected in the first waves of the pandemic, when there were no vaccines yet.


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