Naked Science Forum

Life Sciences => Physiology & Medicine => COVID-19 => Topic started by: Lewis Thomson on 10/01/2022 10:16:58

Title: How can we record the cases daily?
Post by: Lewis Thomson on 10/01/2022 10:16:58

Antony needs help with the following question.

"How is it even possible to have daily recordings of covid-19 cases when half of the population either not take a test or don't believe this covid-19 is real?"

Leave your answers in the comments below...

Title: Re: How can we record the cases daily?
Post by: alancalverd on 10/01/2022 11:11:37

The Press is careful to state "reported cases". Allowing for asymptomatic infected non-testers (say 15%), symptomatic non-testers (15% again?), say 10% who test positive but don't report,  plus 5% of morons, you could reasonably add 30 - 40% to the published number to get closer to the truth.

Title: Re: How can we record the cases daily?
Post by: set fair on 10/01/2022 13:48:43

Zoe gives there estimate of the avaerage number of daily new symptomatic cases in the UK. https://covid.joinzoe.com/ They use people reporting symptoms and then results of their pcr tests. You can multiply this by 1.67 if you assume 40% are infected and asymptomatic and then by 1.28 if you think people will be presymptomatic for two days then, on average, symptomatic for five days. You can change the 1.67 or 1.28 if you think the 40% and 2:5 ratio are not right. Their number peaked on monday the 3rd.

Title: Re: How can we record the cases daily?
Post by: evan_au on 10/01/2022 22:27:31

In Australia, Omicron quickly overwhelmed the PCR testing capacity.
- Health authorities are quickly scrambling to build a web page (one per state) where people can record their RAT results
- And health authorities are talking about making it compulsory to record the results of your RAT

But even then, the results will be underestimated, because many will be asymptomatic, or find that their local store has run out of RAT packs, or not be willing to sit in a queue for 4 hours waiting for a PCR...
- In this case, the best proxy is the Test Positive rate:
- Today in NSW, there were 71,325 PCR tests processed, of which 26,870 were positive, for a Test Positive rate of 36%
- You can infer that total cases are dropping when you see a steady downward trend in the Test Positive rate, lasting at least a week

Between COVID waves, the Test Positive rate in NSW was in the range of 0.1% to 1%.