We should take Cycle Threshold (CT) values of PCR seriously, because they indicate
1. the viral load of an infected patient
2. if he is infectious too
3. if he is at high risk for severe #COVID19
https://science.sciencemag.org/content/370/6512/22

@michaelmina_lab @robertfservice @MartaGaglia #SARSCoV2

[1] Viable virus checked in 3790 positive samples with known CT values. (indicating they were infectious)

Virus could be cultured in
70% samples with CT values ≤ 25.
3% samples with CT values > 35.

"It's fair to say that a person with a higher viral load is more infectious"

[2] Weill Cornell Medicine study: (June 2020)

Number of deaths among 678 hospitalized patients, and their CT values:

35% patient deaths had a CT value ≤ 25 ,
17.6% had a CT value of 25- 30
6.2% had a CT value > 30.

[3] Brazil study: (August 2020)

Among 875 patients, those with a CT value ≤25 were more likely to have severe disease or die.

Conclusions:

[1] Knowing whether CT values are high or low can be highly informative.

“Even with all the imperfections, knowing the viral load can be extremely powerful” ~ @michaelmina_lab

[2] CT values could help doctors flag patients at high risk for serious disease.

[3] CT values could help determine who is infectious/ to isolate them/ track contacts.