k2aggie07 said:
It assumes aggressive testing. What's the point of tracing and isolating if you know you're not seeing every case? Look at the original premise of the study. The more infectious the disease, the higher the hit rate on tracing contacts has to be. But that assumes you have contacts to trace.
I absolutely stand by - look at S Korea and Singapore and see what appears to be working. And look at the US not doing that, and it should be concerning. Even if we take the low end of R0 at 1.5, and 0% asymptomatic transmission requires containment with 50% of contacts traced in the model. If we have silent cases, the contact tracing of known has to offset that.
Do you think we are able to be tracing 50% of total contacts of infection? If we're doing 100% successful tracing that means we have to be identifying half of all cases. You think we're doing that?
Here is your original post:
Interesting paper here:
Feasibility of controlling COVID-19 outbreaks by isolation of cases and contacts.
Quote:
Quote:
Simulated outbreaks starting with five initial cases, an R0 of 1.5, and 0% transmission before symptom onset could be controlled even with low contact tracing probability; however, the probability of controlling an outbreak decreased with the number of initial cases, when R0 was 2.5 or 3.5 and with more transmission before symptom onset. Across different initial numbers of cases, the majority of scenarios with an R0 of 1.5 were controllable with less than 50% of contacts successfully traced. To control the majority of outbreaks, for R0 of 2.5 more than 70% of contacts had to be traced, and for an R0 of 3.5 more than 90% of contacts had to be traced. The delay between symptom onset and isolation had the largest role in determining whether an outbreak was controllable when R0 was 1.5. For R0 values of 2.5 or 3.5, if there were 40 initial cases, contact tracing and isolation were only potentially feasible when less than 1% of transmission occurred before symptom onset.
If you're watching S Korea or Singapore aggressively trace and isolate and that's making you feel good, looking at the cluster that is the US right now should do the opposite.
I overall agree with you in your points. I agree our testing has been crap and has led to undetected cases. I think we have left ourselves vulnerable with the undetected cases.
I am more optimistic that we probably traced back the cases we did know about decently. It is possible we did get 50% of those. How can we even know that now?
I think wtih the mix of the tracing we have already done and leaving ourselves vulnerable with the undetected cases that we might end up with a higher R0 than SK.
I don't know for sure if it means our R0 value is going to be greater than 2, 2.5, 3, etc or not. What do you think it is or will be?
Also, another question, does us having more lead time and changing out behaviors as a nation play into this R0 equation? I have seen A LOT more people simply washing their hands than normal. Maybe some of the behavior changes mitigate the undetected cases. I don't know, I'm just thinking out loud here and saying one factor probably doesn't lead to one outcome. Many factors are at play here - it's a complex issue.
By the way, I'm not in the "just the flu" camp, but I do think reason should win the day.
Also, from the edit, I do want more testing done because I think the denominator is the most important number we need. Facts and data calm fears, and the US is not doing a good job of that at the moment.