Prolonged or severe covid can cause a loss of 6 IQ points

What if contracting Covid-19 makes you stupid? This is according to a study published on Thursday, four years after the start of the epidemic New England Journal of MedicineAccording to which infection with coronavirus will affect our cognitive abilities and our intelligence quotient (IQ).

To measure the effect of the virus on the brain, researchers at Imperial College London studied a cohort of nearly 113,000 British adults. The participants, previously infected with Covid-19, engaged in various exercises. And the results seen vary depending on the severity and persistence of the symptoms.

Impact of persistent symptoms and severe forms

The scientists gave group members a series of tests focusing on their immediate memory, ability to define words, or even find their way through space. A way to assess their memory and their attention and concentration skills. And according to their observations, the more severe or persistent the symptoms associated with Covid-19, the greater the cognitive decline.

Thus, participants who recovered less than a month after their contamination by Covid-19 lost an average of 3 IQ points compared to the group that was never exposed to the virus. Even more striking, the IQ decreased by 6 points in participants with prolonged Covid who still showed symptoms of the disease more than three months after the disease. Public Health France recalls that “the prevalence of post-Covid-19 (or chronic Covid) illness is estimated to be 4% of the general adult population in France, or more than 2 million people”. And that does not surprise 36-year-old Aurelie, who has suffered from chronic Covid for three years: “Since I got the virus, I have lost the ability to concentrate, I can no longer work or read a book, or follow . conversation I’ve been lost in the covid brain fog for this long.

A reduction of up to 9 points was also seen in participants who developed a severe form of Covid-19 requiring hospitalization in intensive care. However, when we know that the average IQ of an adult is around 100, such a drop is not out of the question.

Brain damage due to Covid-19

Since the beginning of the pandemic, doctors and scientists have noted the brain damage caused by Covid-19, and emphasized that it is not just a virus that damages the respiratory system. “I have patients who were infected early in the epidemic and who still describe persistent symptoms such as fatigue, shortness of breath, brain fog and other pain,” Dr. said Benjamin Davido, an infectious disease specialist at the Raymond-Poincare Hospital. Garches. And “several scientific studies have thus “documented the presence of neurological after-effects in the acute phase of SARS-CoV-2 infection – especially cognitive and memory problems,” commented Professor Ziad Al-Ali, Director of Clinical. at Saint-Louis University in the United States. Center for Epidemiology, also in an article published Thursday New England Journal of Medicine

. According to a recent analysis conducted in the United States, after the start of the Covid-19 pandemic, one million American residents of working age reported having “severe difficulty remembering, concentrating or making decisions” compared to any time during the previous fifteen years.

According to the epidemiologist, “the mechanisms of cognitive dysfunction after infection with SARS-CoV-2 must still be elucidated”, but “studies in humans and mice have shown that the infection induces fusion of neurons, which compromises neuronal activity. .Studies show prolonged neuroinflammatory responses, structural abnormalities and accelerated aging in the brains of people with mild to moderate infection with Covid-19.

But the scientists still point to an interesting element: people who had long-term covid but who recovered from it lost an average of 3 IQ points compared to people who only had no covid.

Facilitates the effect through Omicron and vaccination

But that was especially before Omicron. The authors of the study highlight one positive point in their results: patients infected with the Omicron variant and who recovered from their symptoms in less than a month did not experience any decline in IQ. “Perhaps because Omicron initially generates forms that are often less symptomatic, or even asymptomatic, it is quite logical,” Dr. Davido noted.

In the same vein, they also found that people vaccinated against the virus lost fewer IQ points than those who were not vaccinated. The results confirm previous studies conducted in the United Kingdom and the United States, according to which anti-Covid vaccination may reduce the long-term risks of developing Covid and may alleviate persistent symptoms of the virus.

However, the study’s authors admit that their work “does not make it possible to say whether the cognitive functions of people who recover from Covid-19 will eventually improve”, indicating that “further work should be carried out”.