Why is the app telling people to isolate if they have been 'near' (not necessarily 'in close contact') with someone who has tested positive

[StealthPolarBear]

I got one of the messages that flashed up and vanished, which I learned was a system test rather than a proper notice. Bad enough.
But when I looked at the FAQs it told me you should isolate if you've been 'in close contact' with someone who has since tested positive. Fair enough.
Then the question about 'what if I've been near someone who since tested positive' received the same answer!
So if I've walked past someone in tesco for a split second and they then test positive, I should isolate for 14 days?
As far as I can tell that's specific to the app and wouldn't be the official advice from test and trace. So why so different?

Bump

I can't be the only one confused by this

If you walk through air that an infected person had breathed out, then there is risk. More risk of that indoors than outside, which is why places should be well ventilated.
So maybe it is about that risk... you don't need to be a close contact you just need to be near someone infected to have a risk of being infected. Near though is a relative term, so what is being defined as near?

One of several reasons why I wouldn't download the app, even if my phone had the space.

I assumed it was literally passing someone as opposed to close contact.
Yes I agree there's a risk but when contacted by test and trace you aren't advised to isolate unless you've had close contact with a case, surely. So why is the app different?

That's how I'm feeling. I deleted apps for this but the area I live in I'm essentially going to have to isolate after every tesco trip, even wearing a face covering, staying 2m away and washing hands.

And actually the system test stressed me out.

I think near probably means sat at an adjoining table in a restaurant or bar. Not was in Tesco at the same time.

I'm slightly concerned about this app too. Eg I scanned the code on the door as it asked me to when I went to collect a takeaway the other day, I went in and out but I couldn't see how to check out. So how do they know that I was in there briefly and therefore not in close contact with anyone and not sitting down at a table for an hour or more? I don't want to disrupt the whole family because of it. I'm tempted to delete the app.

OK so more than 2m but for a length of time? I've not seen that definition anywhere, where did you sre it?

It's 15 mins.
It's all here faq.covid19.nhs.uk/article/KA-01128/en-us?parentid=CAT-01033&rootid=

That's about close contact. Where is the definition of 'near'?
The technical algorithm doesn't mention the word 'near'.
The faqs in the app itself don't define the terms they use.

@LaVitaPuoEsserePiuBella

One of several reasons why I wouldn't download the app, even if my phone had the space.

Exactly. If I downloaded it in my line of work I would never be able to leave the house . You couldn't pay me to download it

Delete it. Problem solved.

Starting to think you may be right. But I genuinely want to support efforts and would happily have the app if it made sense

And I was actually really impressed with the app when I first installed it

I've deleted it. I had similar concerns and I'm not risking my teens missing school anymore than they already have. The universities have already increased grades needed for entry and my A level teen can't afford to miss school because I happened to be in Tescos with someone who tested positive.

They wouldn't isolate just because you were. You only isolate as a contact of a case (or in this situation a 'nearby' of a case) not a contact of a contact.
If you're sent home as you work with someone who is positive your family should continue to attend work and school unless you (or they) start showing symptoms

Really? That's not what our school says. Anyone in the family isolating then kid can't go in.

Only the contact needs to isolate. The rest of the family only needs to isolate if the original contact gets symptoms

Isn’t the app done on Bluetooth proximities? So if you were in tescos and asking along behind someone for 15 mins your phones would have been in range, if not no issue. My understanding is that the checking in is to stop
An issue where you might be in two ajoining restaurants with a wall between you so phones in Bluetooth contact but actually no risk.

Ok. That seems utterly pointless then, seeing as most kids carry it asymptomatically.

There are two separate things going on:

1. Using Apple/Google tech, your phone will detect if you've been within 2m of people for 15mins+ so if they get a positive, you get the message to isolate.

This tech does NOT record where any contact took place.

1. The QR codes are a more efficient version of leaving your name and details when you visit a place. So if there's an outbreak or someone visited who left their details manually, they can get in touch to work out if you were there at the same time.

Or at least I think that's right from what I could find as I had the same questions!

In terms of passing contact with people who test positive, Test and trace define contact as:

• Under 1 meter for any length of time even with a mask on unless it's full medical PPE
• Within 2 meters for 15 mins or more

Which makes sense as the guidance is that we should maintain 2 meters distance from people outside out house or 1m plus masks where 2 meters is not possible. So we should always be at minimum 1 meter away from people outside our household.

A data expert on Twitter has looked at the code for the app and produced this ; showing that whether you get an alert is dependent on how long your exposure was, your proximity and when they developed symptoms.
So no, you shouldn't get anything from just being in the same Tesco!