Why we should take CT values of PCR seriously

1] First study: 3790 positive samples with known CT values were checked to see if they had viable virus, 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”

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

3] CT values could help determine who is infectious and should therefore be isolated and have their contacts tracked down.

Link: Science Mag, 2 Oct 2020