The emergence of the current crisis caused by the coronavirus (SARS-CoV-2) has meant an extraordinary change in our way of life.
From the moment the World Health Organization considered the situation as a health emergency, information about the disease associated with this pathogen (covid-19) began to spread like wildfire and become an inherent part of our daily lives.
So much so, that in a short time a large part of the population had knowledge about how it is expressed at the clinical level and about the hygiene measures that would allow to contain its very rapid progression.
Certainties and uncertainties about covid-19
Currently the volume of scientific production on this coronavirus is abundant, as thousands of specialists have devoted themselves to unraveling its mysteries. The initial uncertainty begins to give way, at least, to a few certainties.
Among them, that the most common symptoms of covid-19 are muscle pain, fatigue, fever, respiratory problems, headache and loss of taste or smell; as well as that its mortality rate varies according to sociodemographic variables.
The times in which the infection develops are also known: its incubation tends to last between four and seven days after the virus enters the body (with a maximum time window of two weeks). At this time, the first changes in health status are usually identified.
As the days go by, the pathogen disappears from the body and the person progressively recovers their previous physical conditions. This is the most frequent form of evolution.
On the other hand, approximately 30% of the cases would involve asymptomatic patients. These often do not even receive a diagnosis (although they could transmit the disease to others).
However, with the unfortunate accumulation of cases that we are experiencing, a worrying phenomenon is beginning to emerge: some people show persistent symptoms, especially related to intense fatigue.
This symptom of the disease continues to be unknown in terms of its evolution and causes, but its prevalence increases as the virus spreads across the planet.
When do we consider that a symptom persists?
It is understood as persistent symptoms of covid-19 that which lasts for several months after the resolution of the acute infection process, maintaining an intensity that determines the day-to-day life of patients.
This is not an unprecedented phenomenon, as there was already evidence that certain viruses and bacteria could cause it in humans. Among them, other coronaviruses responsible for the outbreaks that hit certain regions of the world at the beginning of this century.
Some examples would be the SARS-CoV detected in Asia during 2003 (which ended up spreading to other countries) or the MERS-CoV (Saudi Arabia, 2012).
Other infections, such as the Epstein-Barr virus or the H1N1 influenza virus (to name a few), have also demonstrated their ability to generate persistent symptoms.
In all these cases, fatigue is usually the symptom most resistant to remission, which has motivated the generic diagnostic label of postviral fatigue.
People who suffer from it report a generalized fatigue, need to rest and difficulties in standing for long periods. In some cases, the intensity of the symptom reaches such a magnitude that it makes it impossible to carry out daily activities.
All of this is added to the difficulties of diagnosis and evaluation implicit in fatigue due to its deep subjective component. This can contribute to the frequent feeling of helplessness and despair in the person who suffers from them.
What we know about persistent covid-19 symptoms
In the case of SARS-CoV-2, some studies indicate that 87% of patients maintain at least one symptom two months after the detection of the first.
Studies are even beginning to be published comparing this form of presentation with myalgic encephalomyelitis, a very disabling and poorly understood disease.
For at least one group of patients, resolution of initial symptoms is only the first stone on the road. Unfortunately, the information we have to explain it is still very little.
The aforementioned persistence has been observed both among those who showed a mild condition and among those who had greater difficulties during the acute process. However, it has been documented more frequently among women and among those admitted to intensive care units. These latter patients often require a longer recovery time.
The severity of the disease and the sex, therefore, could be important to understand this intense fatigue.
What’s behind postviral fatigue
The first explanatory hypotheses investigate the inflammatory and immunological responses that arise naturally during infectious processes. These can occasionally get out of control and lead to a dangerous cytokine storm.
This mechanism in SARS-CoV-2 is attracting the attention of specialists who seek to solve the unknown. The ability of the virus to cross the blood-brain barrier, and certain mediating genetic factors, could also explain the appearance of long-lasting neurological symptoms (such as fatigue).
Finally, there is research that highlights the role of secondary psychological problems (anxiety, depression, etc.) as factors that contribute to exacerbating the subjective experience of fatigue and that tend to accompany it while it persists.
Likewise, many of those who suffered from the disease and suffer residual symptoms report suffering social stigma, the product of fear and ignorance.
As science prepares to empower people with persistent difficulties, it remains essential to inform the public about the infection and its consequences.
Joaquín Mateu Mollá, Adjunct Professor at the International University of Valencia, Doctor in Clinical Psychology, International University of Valencia
This article was originally published on The Conversation. Read the original.
