13 October 2020
Testing for COVID-19 first row was performed using a nasopharyngeal swab taken from the nose or throat. This can be unpleasant. However, this is a quick test, and in the hands of an experienced person it is usually not so bad.
Currently, we mostly do a PCR test, which takes a swab from the nose or throat. A smear full of mucus is sent to the laboratory. This type of test can show false negative results - this is due to the fact that the mucus on the smear did not contain enough virus to detect on the test. This can happen if the smear was done incorrectly or if the amount of virus in the body - the "viral load" - was low (for example, immediately after contact with the patient, when the infection occurred but the virus did not have time to multiply enough).
It is likely that people develop immunity some time after infection and cannot become infected again. But because COVID-19 is new, we don't know exactly how long the body will remain immune to the virus.
If you have relapsed to COVID-19 and an antibody test (ELISA) has shown immunity, then yes, you can hope that you will not be re-infected for at least a few months. Immunity is not a superpower. And antibodies do not last indefinitely. This means that any protection will expire at some point.
The first thing to pay attention to is the percentage of positive tests of all conducted, the so-called detection rate. The lower this figure, the better. The recommended WHO indicator is up to 5% detection among the tests performed. This is evidence that the total number of tests is quite large and allows for early detection of infected.
In Ukraine, this figure was 11-17%, and in some areas more than 25% . This means that we test mostly already patients, and this is not enough to effectively detect all infected.
