I've spent ages looking for an answer to this, without success, but
perhaps someone here can point me at something I've overlooked. Having
been infected, when can I regard myself as "safe"?

Here's the timeline thus far:
19/Apr I was infected (in hindsight) with Covid
22/Apr started to feel rough but LFT was clear.
23/Apr fever, cough, feeling very rough; LFT positive
24/Apr fever, cough, etcetera, plus explosive sneezing
25/Apr bad cough and sneezing but otherwise OK; LFT positive
26/Apr as 25th
27/Apr cough, extreme flatulence(!) but otherwise OK
28/Apr cough but otherwise OK; LFT positive
29/Apr cough, feeling fine
30/Apr slight cough, feeling fine; LFT positive
1/May slight cough, feeling fine
2/May slight cough, feeling fine; LFT positive!!!

I need to decide whether to postpone a couple of things planned for
later this week and wasn't expecting today's LFT to be positive. I think
I vaguely recall reading that the LFT can give a false positive
post-infection due to it detecting bits of RNA debris, but I can't find
this again so may have dreamt it.

On 5/2/2022 1:55 PM, nothanks@aolbin.com wrote:
> I've spent ages looking for an answer to this, without success, but perhaps someone here can point me at something I've overlooked. Having been infected, when can I regard myself as "safe"?
>
> Here's the timeline thus far:
> 19/Apr I was infected (in hindsight) with Covid
> 22/Apr started to feel rough but LFT was clear.
> 23/Apr fever, cough, feeling very rough; LFT positive
> 24/Apr fever, cough, etcetera, plus explosive sneezing
> 25/Apr bad cough and sneezing but otherwise OK; LFT positive
> 26/Apr as 25th
> 27/Apr cough, extreme flatulence(!) but otherwise OK
> 28/Apr cough but otherwise OK; LFT positive
> 29/Apr cough, feeling fine
> 30/Apr slight cough, feeling fine; LFT positive
> 1/May  slight cough, feeling fine
> 2/May  slight cough, feeling fine; LFT positive!!!
>
> I need to decide whether to postpone a couple of things planned for later this week and wasn't expecting today's LFT to be positive. I think I vaguely recall reading that the LFT can give a false positive post-infection due to it detecting bits of RNA debris, but I can't find this again so may have dreamt it.
>
>

No idea how to decode this scenario, but here is a picture.

https://cdn.geekwire.com/wp-content/uploads/2021/02/adaptive.jpg

You're just coming up on 14 days.

Paul

On 02/05/2022 18:55, nothanks@aolbin.com wrote:
> I've spent ages looking for an answer to this, without success, but
> perhaps someone here can point me at something I've overlooked. Having
> been infected, when can I regard myself as "safe"?
>
> Here's the timeline thus far:
> 19/Apr I was infected (in hindsight) with Covid
> 22/Apr started to feel rough but LFT was clear.
> 23/Apr fever, cough, feeling very rough; LFT positive
> 24/Apr fever, cough, etcetera, plus explosive sneezing
> 25/Apr bad cough and sneezing but otherwise OK; LFT positive
> 26/Apr as 25th
> 27/Apr cough, extreme flatulence(!) but otherwise OK
> 28/Apr cough but otherwise OK; LFT positive
> 29/Apr cough, feeling fine
> 30/Apr slight cough, feeling fine; LFT positive
> 1/May  slight cough, feeling fine
> 2/May  slight cough, feeling fine; LFT positive!!!
>
> I need to decide whether to postpone a couple of things planned for
> later this week and wasn't expecting today's LFT to be positive. I think
> I vaguely recall reading that the LFT can give a false positive
> post-infection due to it detecting bits of RNA debris, but I can't find
> this again so may have dreamt it.
>
>

The London School of Hygiene & Tropical Medicine recommends two
consecutive days without a positive LF test before you can say it is gone.

--
Colin Bignell

On 02/05/2022 18:55, nothanks@aolbin.com wrote:
> I've spent ages looking for an answer to this, without success, but
> perhaps someone here can point me at something I've overlooked. Having
> been infected, when can I regard myself as "safe"?
>
> Here's the timeline thus far:
> 19/Apr I was infected (in hindsight) with Covid
> 22/Apr started to feel rough but LFT was clear.
> 23/Apr fever, cough, feeling very rough; LFT positive
> 24/Apr fever, cough, etcetera, plus explosive sneezing
> 25/Apr bad cough and sneezing but otherwise OK; LFT positive
> 26/Apr as 25th
> 27/Apr cough, extreme flatulence(!) but otherwise OK
> 28/Apr cough but otherwise OK; LFT positive
> 29/Apr cough, feeling fine
> 30/Apr slight cough, feeling fine; LFT positive
> 1/May  slight cough, feeling fine
> 2/May  slight cough, feeling fine; LFT positive!!!
>
> I need to decide whether to postpone a couple of things planned for
> later this week and wasn't expecting today's LFT to be positive. I think
> I vaguely recall reading that the LFT can give a false positive
> post-infection due to it detecting bits of RNA debris, but I can't find
> this again so may have dreamt it.

You have it backwards. LFT tends to fail the other way. Failing to spot
people who do have Covid but are not yet at the highly infectious stage.

Most people do recover to being not infectious after about 10 days
maximum if you don't then it might be worth getting checked out.

The PCR test is the more sensitive polymerase test that can give false
positives when you are still shedding fragments of the viral DNA that
have been smashed to bits by your immune system. It was the gold
standard for detecting Covid but it still gave false negatives 20% of
the time! - ie. people with Covid infections who tested negative!

LF is less sensitive than PCR but has a 0.1% false positive rate.
(important for mass population screening)

IOW if you have recently had Covid and LF gives you a positive result
then you very probably are still infectious.

This isn't too bad a summary of the game:

https://www.medicaldevice-network.com/analysis/types-of-covid-19-test-antibody-pcr-antigen/

Basically since you know you have had Covid recently and are still
testing positive it would be totally irresponsible to mix with other
people even though it is now perfectly legal to do so.

--
Regards,
Martin Brown

On 02/05/2022 18:55, nothanks@aolbin.com wrote:
>
> Here's the timeline thus far:

Did anyone else suffer from impotence? In seriousness?
I didn't get a boner for weeks, I thought it was game over down there.

On 03/05/2022 08:29, Martin Brown wrote:

>> I need to decide whether to postpone a couple of things planned for
>> later this week and wasn't expecting today's LFT to be positive. I
>> think I vaguely recall reading that the LFT can give a false positive
>> post-infection due to it detecting bits of RNA debris, but I can't
>> find this again so may have dreamt it.

PCR's definitely do.

>
> You have it backwards. LFT tends to fail the other way. Failing to spot
> people who do have Covid but are not yet at the highly infectious stage.
>

Are you sure? LFT's aren't so sensitive, whereas they have high
specificity, but are you sure a positive test after infection, when the
person is no longer infectious, is considered a false positive?

I know from personal experience, a dirty LFT can give a "false" positive
3 days after it got dirty. A fresh, clean LFT indicated negative. I
don't think the actual active virus survives for three days, so it must
be testing some result of the virus, that hangs around, aka debris.

FWIW, my LFTs stayed positive for eight days.

On 03/05/2022 13:29, Pancho wrote:
> On 03/05/2022 08:29, Martin Brown wrote:
>
>>> I need to decide whether to postpone a couple of things planned for
>>> later this week and wasn't expecting today's LFT to be positive. I
>>> think I vaguely recall reading that the LFT can give a false positive
>>> post-infection due to it detecting bits of RNA debris, but I can't
>>> find this again so may have dreamt it.
>
> PCR's definitely do.
>
>>
>> You have it backwards. LFT tends to fail the other way. Failing to
>> spot people who do have Covid but are not yet at the highly infectious
>> stage.
>>
>
> Are you sure? LFT's aren't so sensitive, whereas they have high
> specificity, but are you sure a positive test after infection, when the
> person is no longer infectious, is considered a false positive?
>
> I know from personal experience, a dirty LFT can give a "false" positive
> 3 days after it got dirty.

Probably why they come in sealed packages and have to be used very
shortly after opening.

A fresh, clean LFT indicated negative. I
> don't think the actual active virus survives for three days, so it must
> be testing some result of the virus, that hangs around, aka debris.
>
> FWIW, my LFTs stayed positive for eight days.

--
Colin Bignell

On 03/05/2022 11:30, R D S wrote:
> On 02/05/2022 18:55, nothanks@aolbin.com wrote:
>>
>> Here's the timeline thus far:
>
> Did anyone else suffer from impotence? In seriousness?
> I didn't get a boner for weeks, I thought it was game over down there.

Apparently, you are not alone:

https://www.nature.com/articles/s41443-022-00540-0

On 03/05/2022 13:29, Pancho wrote:
> On 03/05/2022 08:29, Martin Brown wrote:
>
>>> I need to decide whether to postpone a couple of things planned for
>>> later this week and wasn't expecting today's LFT to be positive. I
>>> think I vaguely recall reading that the LFT can give a false positive
>>> post-infection due to it detecting bits of RNA debris, but I can't
>>> find this again so may have dreamt it.
>
> PCR's definitely do.
>
>>
>> You have it backwards. LFT tends to fail the other way. Failing to
>> spot people who do have Covid but are not yet at the highly infectious
>> stage.
>>
>
> Are you sure? LFT's aren't so sensitive, whereas they have high
> specificity, but are you sure a positive test after infection, when the
> person is no longer infectious, is considered a false positive?

You have misinterpreted what I said.

A positive result is generally definitive that you do have Covid (or in
the case of PCR are still shedding viral DNA). LF is intrinsically less
sensitive but quick to do so if it says you are positive then the odds
are very strongly in favour of you still being infective.

It does have an annoying 0.1% false positive rate though which is a
nuisance if you are doing daily routine screening of millions of people.

A negative test is not really indicative of anything much and cannot on
its own be safely relied upon to mean safe to do things. Two independent
test 24 hours apart is still not great but better (and accepted as OK).

> I know from personal experience, a dirty LFT can give a "false" positive
> 3 days after it got dirty. A fresh, clean LFT indicated negative. I
> don't think the actual active virus survives for three days, so it must
> be testing some result of the virus, that hangs around, aka debris.
>
> FWIW, my LFTs stayed positive for eight days.

It isn't entirely clear at what point people stop being infectious.
But the GI symptoms the OP described are consistent with infection of
the gut which is potentially longer lasting ~20 days. eg.

https://www.medicalnewstoday.com/articles/gastrointestinal-symptoms-in-covid-19-what-do-we-know-so-far#Remaining-questions

and

https://onlinelibrary.wiley.com/doi/10.1002/jmv.26836

--
Regards,
Martin Brown

On 03/05/2022 18:22, GB wrote:
> On 03/05/2022 11:30, R D S wrote:
>> On 02/05/2022 18:55, nothanks@aolbin.com wrote:
>>>
>>> Here's the timeline thus far:
>>
>> Did anyone else suffer from impotence? In seriousness?
>> I didn't get a boner for weeks, I thought it was game over down there.
>
>
>
> Apparently, you are not alone:
>
> https://www.nature.com/articles/s41443-022-00540-0

So I believe, I looked into it at the time.