To think this is going to end badly?

[Notthissticky]

COVID related

My work (secondary school) have just confirmed that pupils and staff will be tested using lateral flow tests. This involves self-administering a throat and nose swab. If you're identified as a close contact of a positive case, you can take daily tests and continue to attend school, instead of self-isolating.

Lateral flow tests have a false negative rate of between 30 and 50 percent, depending on who administers them (pupils as young as 11 in our case). So pupils can continue to mix (there's no social distancing in classrooms) after a close contact tests positive, whilst there's a 1 in 2 chance that they're actually positive. AIBU to think that this is going to result in a disaster of epic proportions???

I think it's better than nothing

I’m not against the lateral flow tests.
But to use them instead of self isolation is fucking idiotic.

How on earth is that better than nothing.

Not sure how my 11 yo will do his own. I did one for him(survey) . He was sobbing... I effectively forced it done... How will he do it himself?

@Viciouslybashed

How on earth is that better than nothing.

For example

10 asymptomatic kids who wouldn't previously request a test.

5-7 found positive
3-5 false negatives

Better than nothing

Surely by the time they get to school to take the test they've already mixed with loads of other pupils in the playground, corridors etc? Seems like a daft idea to me, if a pupil has been in a class with a positive test result person it should be quarantine, no exceptions.

It shouldn't really be used instead of isolating. However if other measures like masks are brought in then it could work.

I think a wise head will work out how to use the tests to the best of their advantage. Ours wants everyone to use local test centre a couple of days before we are due back. Then we email in the result. She then plans to use tests on those that didn't do that.

I am interested to her what she will work out for the test vs isolating problem but have faith she will find away around guidelines that works

Better than nothing

But previously all of those false negatives would be at home for ten days-working safely online and mixing with nobody.

Under this (stupid) plan, they’ll be on the bus/train and mixing with 30 different children every hour-plus staff.

Not ‘better than nothing’ at all, no.

Its instead of self isolating, formerbabe. And it's not as good as that at not spreading it in school. However, a false negative rate of 50% doesnt mean a probability of 50% that a negative is a positive, as the OP suggests.

Lateral flow tests are suitable for screening for asymptomatic cases, in which case they are better than nothing. Schools will be doing this, which I applaud. However, they will also be using them as a substitute for self isolating. They are absolutely not suitable for this; for comparison, NHS staff are screened in the same way. The NHS, however, still requires close contacts to self-isolate. You couldn't make this shit up! Please refuse consent for daily tests if your child is a close contact of a positive case and self isolate instead.

@TheFallenMadonna

Its instead of self isolating, formerbabe. And it's not as good as that at not spreading it in school. However, a false negative rate of 50% doesnt mean a probability of 50% that a negative is a positive, as the OP suggests.

Can you explain why a false negative rate doesn't mean a 1/2 chance of a negative being a positive? Genuine question! I have a good grasp of statistics, but probability is trickier.

Oh I see...yes as @Notthissticky says better than nothing if testing for asymptomatic cases but not as a substitute for isolating.

I agree, notthissticky.

I have withheld consent, and I normally consent to everything.
The way I see it, if DD is in contact with a positive case, I want her at home. If she takes a test and is negative, then yes, maybe she is negative. But there is a chance she is positive, but thinking she’s fine. So off she goes on the bus, and into school...
And whether she is positive or negative, there is a high chance she will be sitting with people who are in because their test showed a false negative. So she could then pick it up from them, even if she didn’t get it first time round.

I’m not happy about that. I’d rather just keep her at home in those circumstances.

Some Secondary school children will just say no and refuse testing

Because quite rightly because of bodily autonomy

And we will need a whole set of rules about whether they can be in school.

Can you even imagine how disruptive this will be with 1600 of them all standing outside in the cold 2 metres apart ?

It’s frankly a ridiculous concept. Testing in principle is a good idea but not instead of self isolation. That will make schools every more unsafe.
If it’s that good an idea it should be rolled out to everyone and no need for anyone to isolate.

If there were 50% false negatives it would mean that 50% OF THE PEOPLE WHO WERE POSITIVE would test negative.

All the people who WERE actually negative would be testing negative as well. So if there were 1000 children in a school and 6 of them were positive (a realistic number), then with a 50% false negative rate you would get 3 children test positive who were positive, 3 children test negative who were actually positive, and 994 children test negative who were negative.

So 3/997 would be wrongly told they were negative. Which is pretty bloody far from 1 in 2!

@babybythesea

I agree, notthissticky.

I have withheld consent, and I normally consent to everything.
The way I see it, if DD is in contact with a positive case, I want her at home. If she takes a test and is negative, then yes, maybe she is negative. But there is a chance she is positive, but thinking she’s fine. So off she goes on the bus, and into school...
And whether she is positive or negative, there is a high chance she will be sitting with people who are in because their test showed a false negative. So she could then pick it up from them, even if she didn’t get it first time round.

I’m not happy about that. I’d rather just keep her at home in those circumstances.

I have consented to be tested for screening purposes but refused to be tested if I'm a close contact. Are you refusing all testing for your DD? I hadn't thought it through as much as you but I totally get where you're coming from.

If you tested 100 uninfected people with a test with 50% false negative rate, you would get 100 negative results, and it would mean 50% of them were wrong. It's the probability that an infected person will return a negative result, not a 50% chance that the test is wrong for every subject.

It wouldn't mean 50% were wrong

I don't think that there is anywhere else in the world where they are considering this

@formerbabe

I think it's better than nothing

If the results are inaccurate it’s no good. Waste of money.

Discussed with my DS who is 12. He's not confident he will be able to administer the test do we aren't giving consent

Although I was on SfE webinars today where this was brought up a lot and we were reassured frequently about its sensitivity.

@Notthissticky it's something to do with prevalence in the community at the time. If there are lots of cases in community, then there is a higher chance that a negative result is false than if there are fewer cases at the time. And vice versa for false positives.
I've read the stuff that came with the test kits but not entirely sure I understand it.
@Santaisironingwrappingpaper not to be rude but the tests are usually uncomfortable not unbearable - did you stick the swabs up too far?

It's not better than nothing, because it will give people false confidence that they're COVID-free and can therefore be less vigilant about distancing etc. Nothing IS better than a significant rate of false negatives.