Originally Posted by: Roundtuit Originally Posted by: Roundtuit Would you trust a Covid "passport" based upon negative test?
Seventeen responses and not one reply addressing the above.
In the absence of any evidence to the contrary, i.e. obvious symptoms, yes I would. Whilst it may not be perfect, it is better than nothing. The issues with the private testing company may have reduced confidence in the procedure, but given that over 8.5m (by the end of today) will have tested positive, and this issue effects around 50,000 test results then I would say the accuracy still seems to be quite high.
The period of false testing was a total of 35 days (8 sep - 12 oct) during that time there were very roughly
35*30000 = 1.05m positive cases, so around 4.5% of cases were missed (through testing). This would still place the accuracy of the tests at around 95%.
As an aside, assume you had a random sample of 10,000 people attending an event with COVID passports. Assuming 1 in 60 were positive at the time (source) then we would expect
10,000 / 60 = 167 people to be infected.
Currently the number of assymptomatic cases is really hard to measure, with estimates between 1.74% and 78.3%, but an average of around 25%. We would hope those with symptoms would stay at home, leaving
167 * 0.25 = 41 people without symptoms attending the event,
Without the passport those people are free to infect people during the event. We can argue about the efficacy of PCR/LFT tests, but every person we can knock off those 41 people can only be a good thing. Let's be conservative and suggest 80% efficacy. This would mean we reduce that number of positive cases attending the event to 8 people.
The Delta variant has an R0 number of somewhere between 5 and 8. Let's call it 5 to be fair. Those 41 people would infect 205 people (I know it won't be just in the event, but just to get the point accross). With passports it would be 40 people. So the passports would mean that in this round the total number of people with the virus falls from 167 to 40. Without passports the number rises from 167 to 205.
If we repeat this process going forward, with passports the virus would cease to be very soon, without it will soon infect the whole world again.
This is why I trust a test that has a few flaws over no test at all.