Start from the beginning
In late April, Korean doctors reported on 263 patients, tests for the presence of viral particles which were again positive after people have recovered from coronavirus infection. These people were considered to have recovered, and the penultimate test found the virus in their body. This is not the first such news: a similar message has already been received from Japan and China.
This can be explained
reactivation of the virus
Let’s start with the latter because it is considered the most likely. The head of Committee of the Korean Center for control and prevention (KCDC) ON Mini-don (Oh Myoung-don) believesthat the positive result of tests is not associated with recurrent disease. His explanation — what the test found not a virus and their fragments, embedded in the epithelium. Test this difference is not visible: it shows the presence of viral RNA in the sample, but what kind of virus it belongs — able to reproduce its “debris” — can not.
There are other disruptions of test systems: for example, false negative results — showing the absence of viral RNA where it is, and when a large volume of poor quality tests will inevitably become noticeable. At the stage of recovery of viral particles in the body is already small, and the chances to “catch” their dough is also falling.
Judging by historical data, the remains of the virus can persist in the body for a long time after recovery. In some patients the virus is detected in sputum and stool in a couple of months after the onset of symptoms. In the case of Korean patients About Mine-don indicates that replacing half of the epithelium, which lined our respiratory tract, occurs on average three months, and suggests that RNA virus could get into the trial and a month after recovery.