Data on asymptomatic positive Covid cases....if you can only test with symptoms?

[dameofdilemma]

I read another post stating 1 in 3 cases are asymptomatic.

Just wondered if anyone (with more scientific knowledge than me) knows how the data to support this is gathered (as only those with symptoms are entitled to tests)?

The ONS do a weekly survey where they send tests to a random selection of the population. Presumably 1/3 of those come back positive.

Also people who go into hospital are often tested on arrival, 1/3 of them test positive dispite no symptoms.

Furthermore there are staff such as medical staff who can have tests without symptoms, such as those having the twice weekly lateral flow tests.

Hope that helps :)

More info on the ONS survey here www.ons.gov.uk/peoplepopulationandcommunity/healthandsocialcare/conditionsanddiseases/bulletins/coronaviruscovid19infectionsurveypilot/18december2020

I can’t answer the question but I’d like to know the answer too. I’ve also wondered how on earth asymptomatic people know they’ve got the virus unless someone they’ve been in contact with is showing symptoms? It seems really hard to track if there’s so many people walking around perhaps feeling slightly under the weather, but with no real symptoms.

There are also tests on asymptomatic people; lateral flow tests and tests on specific key workers such as NHS age care home workers for example.
"Asymptomatic" is self-reported; if someone has chosen not to say they had a fever/ cough, or a less specific symptom like diarrhoea or runny nose - then they are listed as asymptomatic. If they had the virus a month ago without a test and now have no symptoms but the body is still excreting dead virus, they are now "asymptomatic"(actually post-symptomatic). If they are going to get symptoms in a day or two they are "asymptomatic" because it isn't checked back on, but they are really pre-symptomatic.
Quite a variety of reasons why a word can't be taken out of context of peer-reviewed research.

Also - people catching a plane, REACT study, anyone going into hospital as a patient etc etc etc.

No @@KitKatastrophe - not one third come back positive, but one third of the positives have reported no symptoms at the time the test was taken.

@YukoandHiro

No @*@KitKatastrophe* - not one third come back positive, but one third of the positives have reported no symptoms at the time the test was taken.

Oh that's what I meant, apologies

Thanks all, this is really helpful.

Yes as many people have mentioned there are lots of other studies going on. My DM and DB were both part of a UK Biobank study where they were tested every month. In the first lockdown I had the ZOE app and between April and July they asked me to do 3 tests. I'm NHS staff so now do lateral flow tests twice a week. So there's lots of testing of different groups going on.

My London borough sent posted letter around asking people to book a test to see how many people are asymptotic. You can do it if you want or not.