Over the past week, the university hospital of the Free University of Brussels in Jette (UZ Brussel) has been systematically submitting all new patients to a lung scan to detect the presence of the coronavirus (Covid-19).

The test reveals lesions on the lungs typical of the virus, and is administered whether patients are admitted with respiratory problems or not.

Now the hospital has announced that 8% of patients tested show signs of being infected by the virus without realising it, and without showing any of the other symptoms of the disease – fever, a persistent cough, trouble breathing etc.

The test involves a CT scan of the lungs, which provides a result faster than the conventional tests that are used more selectively.

“We are doing it to protect our staff and other patients, but also for the patients themselves,” said Professor Johan De Mey, head of radiology.

It has been stressed from the start that many people can be infected by the virus but show no signs or suffer no symptoms. Nevertheless, they remain contagious and can pass the virus on to others if precautions are not taken. The UZ Brussel tests confirm that, and also give an idea of the extent of the problem.

In the first two days of CT testing, 50 patients had been scanned, and five of them showed signs of the virus. They were then tested using the classic test, which confirmed the diagnosis. None of those affected had shown any symptoms.

By the end of a week the proportion had dropped slightly to 8%, from a group that included two women who had presented at the maternity department to give birth.

“The group we have now identified has absolutely no respiratory problems,” Prof De Mey said. “These are people with appendicitis, fractures and other problems. Our suspicion is, as we have said before, that there are people in the population walking around without symptoms but infected with the virus, and even showing signs of the effects of the virus on their lungs.”

Alan Hope

The Brussels Times

