COVID-19 statistics is part of our everyday life. We wake up with COVID-19 and go to bed with COVID-19. We constantly hear that despite so-called COVID-19 measures there is an increase in cases and infections.
But what actually is a case or an infection?
-> Case is when the person has both clinical and laboratory characteristics of a certain disease, which are diagnosed by a physician.
-> Infection is invasion and growth of germs in the body.
How do we measure cases or infections during the COVID-19 pandemic?
-> We use as a measuring unit the number of positive PCR tests. If the test is positive is called a case or an infection.
What exactly is the PCR test used for COVID-19 detection?
- It is actually RT-PCR – a molecular biology technique which lets us detect parts of the viral RNA (the genetic information in some viruses is not stored as DNA but RNA). It is RT because it first converts (transcribes) RNA to DNA. It is necessary since only DNA can be multiplied (amplified) at the levels which can be detected by fluorescence. Every multiplication is called threshold cycle or Ct. Since the SARS-CoV-2 is RNA sequence this is the only way to detect it.
What can the PCR test tell about the virus?
- The PCR test can tell if there are some parts of RNA in the cell.
What PCR test can’t tell us about the virus?
- It can’t tell if there is an active virus.
Can the PCR test show if there is a COVD-19 infection?
Can the PCR test show if the person is a case or an infection?
Is it possible a healthy person to have a positive PCR test?
- Yes. The tests are very sensitive and can detect traces of the viral RNA.
As you can see from above positive PCR tests aren’t cases nor infections.
Mixing the number of healthy people with positive PCR tests with cases/infections leads to creating death rate which doesn’t exist.