We already know that the percentage of deaths from Covid-19 is superior to that of the flu. But for those who would still find this death rate uninteresting, what about the direct, long-term impacts of the disease, which set it apart from the seasonal flu? We take stock.
A direct effect: respiratory distress
In the majority of cases, the SARS-CoV-2 virus, which causes COVID-19, causes only a mild form of the disease. The lucky ones are rid of the virus after two to three weeks. But about one in five people develop severe symptoms that can lead to intensive care. We think in particular of the acute respiratory distress, linked to overreaction of the immune systeme. This complication sometimes occurred during an infection with the influenza virus (the flu), but it is much more common with the coronavirus.
In the end, the death rate fluctuates by region and by age category: several studies now point to a range oscillating between 0.5 and 1%, which remains much higher than for influenza.
More long-term effects
But even after the hospital, there are consequences. In 5-10% of patients cured of COVID-19, the slope is difficult to go up: they drag symptoms sometimes quite heavy for weeks, even months. These symptoms are not only respiratory, as specialists thought so in the beginning. Today, is a site that the disease can cause tachycardia, muscle and joint pain, and exhaustion more than 60 days after the onset of the disease.
Are also mentioned of neurological damage ranging from simple cognitive difficulties, fatigue or loss of taste or smell, to cases of headache, stroke and epilepsy. BBC reported that at the end of June, there were already more than 300 studies on these neurological abnormalities observed in patients with Covid-19.
People with residual symptoms now speak of their reality as « syndrome post COVID-19 ». They are also found by the thousands in online support groups. As the virus has only been known for seven months, it is not known how long these repercussions last. Follow-up studies carried out with victims of the SARS epidemic in 2002-2003 also reported lasting sequelae, such as exhaustion, of the Depression and an loss of respiratory function.
In comparison, influenza viruses cause much less damage. If various complications are possiblelike pneumonia, these are usually short-lived — less than 2 weeks.
Even in the case of two strains of influenza that have caught the imagination, H1N1 in 2009 and H7N9 in 2013, the long-term sequelae seem mostly respiratory. A study involving 22 survivors of severe pneumonia following influenza A (H1N1), concluded that a year after leaving intensive care, although all had recovered most of their lung function, there were differences between intubated patients life support and those who were not. A similar study involving 37 French survivors noted a measurable decrease in lung capacity one year after leaving intensive care.
Similar finding with the H7N9 influenza (A), which struck in Asia in 2013: a study published last March evokes permanent damage to their lungs a year after they were hospitalized. However, remember that the scale is not the same: for the H7N9, WHO identifies officially 1,500 laboratory-confirmed cases between 2013 and 2018, and some 650 deaths. By comparison, in mid-August, Covid-19 reached the 20 million officially reported cases around the world, in just seven months.