People who have had Covid-19 have lower IQs than those who managed to avoid the disease. But it is still too early to draw conclusions

A new study, developed by researchers at Imperial College London, concluded that Covid-19 can reduce IQ, especially in patients who have experienced serious infections.

This is not the first study that links Covid-19 to effects related to cognitive decline: for example, a study published in The Lancet in July 2021, developed by Imperial College London and involving more than 81 thousand people, concluded that there is an association between people who have had Covid-19 and lower performance in tests that assess IQ.

According to the team, some of the most notable problems were found in reasoning and problem solving, for example.

In October of that year, researchers at Mount Sinai Hospital in New York, USA, concluded that brain fog (brain fog, in English), scientifically known as mild cognitive impairment, can last for months after Covid-19 infection. At the time, the team also said that this situation could happen in patients who did not require hospitalization, although there is a greater probability of the same happening in patients who were hospitalized.

Last year, in July, researchers at Imperial College London concluded that brain fog is comparable to 10 years of aging. When analyzing the impact of SARS-CoV-2 coronavirus infection on memory, they discovered that cognitive impairment was higher in people who had tested positive and had more than three months of symptoms. The same study, which can be consulted in the scientific journal The Lancetalso discovered that this “mental fog” could last for almost two years.

Now, in this new study, the team found that participants who managed to avoid the disease generally performed better on intelligence tests; Volunteers who needed to be hospitalized had worse results in these tests.

To carry out the study, researchers analyzed data from more than 112 thousand volunteers, who carried out Covid-19 tests during the pandemic, discovering that patients who had been admitted to Intensive Care Units (ICU) obtained, on average, around nine IQ points lower on exams than those who avoided infection.

Furthermore, the team concluded that volunteers who reported having suffered long Covid had a score six points lower than volunteers who had not been infected.

However, volunteers who had suffered an infection with mild symptoms also obtained a score two points lower than those who avoided it.

Another conclusion from this new research was that an infection with the “original” coronavirus was associated with a greater drop in IQ; Infections with the variant called Ómicron led to small differences in the tests.

Despite the results, Adam Hampshire, main author of the study, states that they should be interpreted with caution, as the participants were not evaluated before they were infected, meaning it was not possible to compare the results of their IQ before and after of Covid-19 infection. It is still too early to accurately understand the impact of Covid-19 infection on cognitive abilities, experts say.