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The aftereffects of COVID-19 are “no worse than the flu”? False

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We already know that the percentage of deaths from COVID-19 is higher than from the flu. Still not interested in this mortality rate? What about COVID-19’s long-term impacts that distinguish it from the seasonal flu? The Rumour Detector sets the record straight. 

A direct effect: respiratory distress 

In most cases, the SARS-CoV-2 virus, at the origin of COVID-19, only causes a mild form of the disease. The luckiest victims get rid of the virus after two to three weeks. But about one person in five develops severe symptoms that may lead to intensive care. One such condition is acute respiratory distress, linked to an excessive immune response. This complication sometimes occurred during an infection with the influenza virus (the flu). But it is much more frequent with the coronavirus. 

Finally, the death rate fluctuates by region and by age category. Several studies now point to a range fluctuating between 0.5% and 1%. This is much higher than for the flu.


Long-term effects are more numerous 

Even after the hospital, there are after-effects. In 5% to 10% of patients cured of COVID-19, the road to recovery is difficult. They live with symptoms that are sometimes as serious as COVID for weeks, and even months. These symptoms aren’t only respiratory, as the specialists initially thought. Today, we know that COVID can cause tachycardia, muscle and joint pain and exhaustion, over 60 days after the onset of the disease.  

Neurological difficulties are also mentioned.  They range from simple cognitive difficulties, fatigue or loss of taste or smell to headaches, stroke and epilepsy. At the end of June, the BBC reported, there were already over 300 studies of these neurological anomalies observed in COVID-19 patients. 

People coping with residual syndromes sometimes refer to their reality as “post-COVID-19 syndrome”. Thousands of them can be found in online support groups. We’ve only known about this virus for seven months, so nobody knows how long these after-effects will last. Follow-up studies with victims of the 2002-2003 SARS epidemic also referred to lasting after-effects. They included exhaustiondepression and loss of respiratory functions

In comparison, the influenza viruses cause far less damage. Various complications are possible, such as pneumonia. But they are generally short term – less than 2 weeks.  

Even for two flu strains that captured the imagination, H1N1 in 2009 and H7N9 in 2013, the long-term after-effects mainly seem to be respiratory. A study covered 22 survivors of severe pneumonia after influenza A (H1N1). One year after they left intensive care, differences were noted between patients who were intubated on an artificial respirator and those who weren’t. That’s even though they had all regained most of their respiratory functions. A similar study of 37 French survivors noted a measurable reduction of lung capacity one year after they left intensive care.  

There were similar findings for influenza (A) H7N9, which hit Asia in 2013. A study published last March mentions permanent damage to their lungs one year after hospitalization. However, we must remember that the scale isn’t the same. For H7N9, the WHO officially identified  1500 cases confirmed in the laboratory between 2013 and 2018, and about 650 deaths. In comparison, in mid-August, COVID-19 reached 20 million officially reported cases all over the planet, in only seven months.  


This article was originally published on the website of L'Agence Science-Presse (French only).


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