To think that when antibody tests

[GenderApostate19]

become available, those of us who have tested negative should be first in line to get them?
30% false negative rates are insanely high and will surely get higher with all the self administered swabs?
There are going to be up to 30 out of every 100 tested going out and about thinking they are ok to do so, even though they actually have it.
The thing I really, really want to know is - if all if us with clear symptoms don’t have covid, what the hell do we have ?
Surely they would know by now if there was another virus/ illness knocking about that mimicked covid symptoms and, more crucially, would be telling people about it.

My understanding is it will be a while before we have anything reliable. But if/when we do it should surely be based on need. Vulnerable people should be offered it first as it would make the biggest difference if they were immune (and the test could actually tell that). I have NHS colleagues who suspect they had it but weren't tested. My SIL thinks she had it because her friend and work colleague did (confirmed with a test). I don't see that people who were able to get a test should be necessarily prioritised over those who weren't. I agree it is worrying it might not be accurate, but it's still 70%+ that you didn't have it, compared to people who have no idea. Also, if you don't have the antibodies it won't answer what you did have. I had a horrendous virus before lockdown and can't help thinking 'maybe?' even though I know it is extremely unlikely due to the date.

But they're not even sure you'll have immunity so it's a bit pointless.

@hopeishere they've decided that it's not possible to get it twice.
I'll find the article and post it.

No; there are people who had it but couldn't even get tested at the beginning of the outbreak, they were only testing if you were admitted. They have more likely had it than someone who tested negative.

There was a good discussion of this on Radio 4 on I think Thurs night.

It depends what you want the test to show.

For an individual to know if it is safe to go back to work then yes you need lower rates of false negatives. Upwards of 98% and preferably higher.

But if you want to know within a population then a test with more false negatives is acceptable as providing the rate of false negatives is fixed you can do a mathematical fix to work out the real proportion. This could be helpful if you say wanted to reduce lockdown regionally.

This isn't the original paper - it won't me link it, but it gives the info.

news.sky.com/story/coronavirus-scientists-conclude-people-cannot-be-infected-twice-11981721

They have to get a good antibody test.

One that is highly specific and highly sensitive. It's also really important who you test - are you 'screening' a general population or are you giving them to a population who you suspect may have been infected.

That makes a massive difference to the predictive value of a positive (and a negative) test.

If people get the home tests, we are going to see an influx of people 'asking if they can see a line'.

That article is really confusing!

In an update to its guidance, the WHO warned there was "no evidence that people who have recovered from COVID-19 and have antibodies are protected from a second infection".

I’d hope they consider the nhs, keyworkers and shielded first. We’re not just on lockdown when shielded but having to stay away from people in our houses, no walks, no outside world at all and no end in sight despite all the talk of easing lockdown.

Over a million people thrown into a mental health nightmare being told to protect the nhs as we’ll likely be very unwell or die and might not be able to get help we need.

Again from the Independent

But, just because you recover from the virus does not mean you cannot catch it again, WHO confirmed in a statementt* released on 24 April. "There is currently no evidence that people who have recovered from Covid-19 and have antibodies are protected from a second infection," the organisation said.

There is a good antibody test being rolled out in Europe already, it's over 99% accurate.

t's over 99% accurate

Accuracy is not quite the correct word to use with such tests.

It's important to know the specificity, the sensitivity and the prevalence of the thing you are looking for in the population you are testing.

I think that the main problem is for keyworkers - with a negative test, they will be pressured into coming back to work too early.
I think the advice should be that if you have symptoms but test negative you should still isolate for at least 10 days from onset of symptoms. Official gov.uk advice is that negative test = Straight back out there 🙄
DH rang work to tell them he was negative but would not be back to work on Sunday - 1. He’s still rough and there is no way he could manage a 12 hour shift - he’s an engineering manager in a huge food factory.
2. WHO guidelines say isolate for 14 days with symptoms, it’s day 7 today for us. His employers have adopted the 14 day rule for symptoms but he has been the 1st person with a neg test and they have NO idea what to do so he just told them he was sticking to 14 days.

The covid team are still calling him daily as they are sure he has it and the doctor said to definitely carry on isolating for another week.
Redcherries - my Sister is shielded too, it is a nightmare. How many shielded people are likely to have antibodies though? The whole purpose is to stop the most vulnerable getting infected, they should be first in line for any vaccines for definite, but I’m not sure antibody testing will be any use.

Well, before shielding I travelled to four other countries between the end of January and the middle of March, including two visits to Boston and several days in New Orleans, Seychelles, Budapest and Canada so I reckon we had a good chance of coming into contact with it. New Orleans and Boston both had huge surges a week after we were there.

We haven’t been shielded since the very beginning of the virus.

So even shielded people who are potentially infected can be asymptomatic or have very mild symptoms ?

You assume that someone with severe health problems will become very ill - my Sister was told if she gets it, it will kill her! Severe Copd, asthma, diverticulitis and various other problems.

No; there are people who had it but couldn't even get tested at the beginning of the outbreak, they were only testing if you were admitted. They have more likely had it than someone who tested negative.

^^
Surely this? Why would they mess about testing people who have already tested negative before testing those who have had the symptoms but weren’t able to have a test?

I would say those who tested negative are last in line.

Of course at risk people could have mild versions, its not a guarantee it will kill you its just far more likely, however my risk is slightly strange one. I'm at no increased risk from the virus than anyone not shielded but I can't fight bacteria, its the risk of a secondary infection that could kill me or mean I'm taking up a valuable bed. I have a high risk of organ failure, sepsis, pneumonia and infection of the heart.

I thought main useful purpose was to allow carers or other key workers to get back to work. Not much value for ordinary people.