Half of the positive cases are not even contagious

Scientists have evaluated 190,000 PCR tests on more than 160,000 people. The result: PCR tests are not a suitable method for assessing the state of the epidemic. Many of those who test positive for the virus are not contagious at all.

Wert . threshold cycle

Taking into account the cycle threshold value, according to the researchers, the informative value of PCR tests can be increased. This shows how high the risk of infection is.

The higher the CT value, the lower the concentration of the original virus in the sample. Symptomatic cases tend to have lower CT values ​​than asymptomatic cases. Of the CT value of 25, subjects who tested positive for the infection were no longer considered.

According to the results of the research team, only 40.6% of the test results showed that the CT values ​​were less than 25. The majority of reported cases of coronavirus infection had a very low level of virus that was not contagious.

‘No basis for fighting epidemics’

“According to our study, a positive RT-PCR test alone is not sufficient evidence that those tested can also transmit the coronavirus to other people. The number of people tested positive for SARS-CoV-2 calculated,” says first author Professor Dr. Andreas Stange. Ultimately it should not be used as a basis for anti-epidemic measures such as quarantine, isolation or lockdown.”

Since the beginning of the epidemic, the incidence value determined by PCR tests has also been used as a justification for the lockdown measures in Austria.