37% of patients with Covid-19 have symptoms six months later

37% of patients with Covid-19 - more than one in three - will continue to have at least one symptom after three to six months, according to a new British scientific study, which confirms that long-term Covid-19 is not uncommon .

Researchers at the University of Oxford and the British Institute for Health Research (NIHR), published in the medical journal PLoS Medicine, studied data on more than 273,000 people infected with the coronavirus. The most common symptoms of so-called "long Covid-19" have been found to be respiratory problems, abdominal symptoms, fatigue, muscle aches and anxiety or depression.

"The findings confirm that a significant proportion of people of all ages can experience a range of symptoms and difficulties six months after Covid-19 infection," lead researcher Dr Max Tuckett of the NIHR told the Guardian.

Symptoms that persist for months are more common in those who had a more severe illness and needed treatment, and are somewhat more common in women than in men. The latter, especially the elderly, are more likely to have difficulty breathing as well as cognitive problems, while younger women and women suffer more from headaches, abdominal pain and psychological problems. Those who did not need to be hospitalized are more likely to have headaches later.

In comparison, people with the flu have much rarer lasting symptoms. Symptoms of long-term Covid-19 are estimated to be at least 50% more common than influenza infection.

Another British study found that at least one in ten high school students had symptoms of long-term Covid-19.

In all, an estimated 970,000 people in the UK suffer from long-term symptoms after Covid-19, of which 384,000 continue to have at least one symptom one year after infection.

The seven symptoms

Seven symptoms can be used to diagnose Covid-19, especially if a test is not available immediately. A new study by researchers at Imperial College London, also published in the journal PLoS Medicine, found that people with all seven of these symptoms were more than 75% more likely to be infected with the coronavirus. Symptoms are: Loss of sense of smell, loss or disturbance of taste, fever, persistent cough, chills, loss of appetite and muscle aches.

The researchers studied molecular test (PCR) results for 1.15 million people over the age of five. These people were asked about their symptoms a week before the diagnostic test.