Scrutable

Professor Tim Spector, has been leading the really important COVID symptom study at King's College London. I've head him make a lot of great contributions to discussions of COVID-19 on TV and radio. However, today I was very surpised to hear him make a very bold claim on BBC Radio 4's Today Programme. To quote his exact words....

If you do have a runny nose, or congestion, or sneezing, that's really a sign you absolutely do not have COVID.

Not...

"...you probably do not have COVID."

Not...

"...you almost certainly do not have COVID".

But...

"...you absolutely do not have COVID".

OK - it may very well be the case that the COVID symptom study shows that a runny nose and congestion is not diagnostic of COVID (i.e. no more common in people who test positive than those who do not). But it cannot be the case that having a runny nose or congestion is a 100% specific indicator that you do not have COVID? Can it?

Even if the US CDC are wrong in their assertion that "congestion or runny nose" can be a symptom of COVID...

https://www.cdc.gov/coronavirus/2019-nc ... ptoms.html

...you could still have coinfection with a rhinovirus. At universities will we have students who heard this interview turning up at seminars with streaming noses asserting "I've got a runny nose so I can't have COVID - Professor Spector said so"?

Having a broken leg is not a symptom of COVID - but having a broken leg is not a sign you absolutely do not have COVID.

In any case, plenty of studies have shown some COVID patients do have rhinorrhoea...

13.5% in this group of children...
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7327402/

16% in this group...
https://pubmed.ncbi.nlm.nih.gov/32725955/

Runny noses might not be good for identifying COVID-19 cases - but a runny nose does not, and could not, rule it out absolutely.

(To cut him some slack he did say that a runny nose is "a sign you absolutely do not have COVID" rather than "a sign you absolutely are not currently infected with SARS-CoV-2". But not sure that makes a huge difference from a public engagement point of view).

That does seem a tad dangerous.

I mean, certainly, the vast majority of people who currently have runny noses (I include myself, I currently feel like sh.t thanks to the bagkitten kindly sharing her cold with me) will not have COVID. But that doesn't mean that none of them will because, as you say, even if it's not a symptom, you could have a cold and COVID at the same time.

That said, I do think that there would be a benefit to amending the current testing advice. I know of quite a number of people who have (after some considerable effort) managed to get tests for their kids who are suffering from this same cold. In their cases, their kids have had a persistent cough and/or high temperature associated with it. Following current advice, that means either getting a test or self-isolating for 10 days, and 14 days for the rest of the family so since for some of them that would be 2 weeks without pay and 2 more weeks of their kids being off school, they've been making huge efforts to get tests. Even when the parents are 99% sure that it's a cold. So they're doing the right thing and doing what they're told, and then getting told off for clogging up the testing system. So yeah, testing advice needs changing, although I'm not sure that "look, if 50% of your child's fellow pupils are all suffering the same symptoms and you're currently sneezing your head off while you're reading this, then it's so unlikely that it's COVID that you can probably crack on with life as normal, unless other symptoms materialise" is quite the right wording. Obviously, the best thing would be to have enough testing capacity for everyone to have a test at the slightest reason, but that's a pipe dream right now.

bob sterman wrote: Thu Sep 17, 2020 12:10 pm In any case, plenty of studies have shown some COVID patients do have rhinorrhoea...

13.5% in this group of children...
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7327402/

16% in this group...
https://pubmed.ncbi.nlm.nih.gov/32725955/

Do either of those studies compare with the % of kids with those symptoms in the general, non-COVID infected population? Because, especially when the bagkitten was younger, I reckon she probably had a runny nose or congestion for at least 10% of the time, more at this time of year. So it feels like 13-16% of kids having rhinorrhea might be a pretty standard percentage of any sample of young kids at any time during autumn/winter/early spring so maybe not evidence at all that it's a possible symptom of COVID.

I quickly scanned the first study and didn't see anything but I might well have missed it, and I haven't checked the second yet.

I’ve got a runny nose right now so I’m glad to hear that I haven’t got COVID.

bagpuss wrote: Thu Sep 17, 2020 12:48 pm

bob sterman wrote: Thu Sep 17, 2020 12:10 pm In any case, plenty of studies have shown some COVID patients do have rhinorrhoea...

13.5% in this group of children...
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7327402/

16% in this group...
https://pubmed.ncbi.nlm.nih.gov/32725955/

Do either of those studies compare with the % of kids with those symptoms in the general, non-COVID infected population?

No they don't. I expect you're correct - the % with runny noses is probably not that different to the general population at this time of year.

Only posted them to show that people with positive COVID-19 tests CAN have runny noses. Not that it was particularly diagnostic.

bob sterman wrote: Thu Sep 17, 2020 12:53 pm

bagpuss wrote: Thu Sep 17, 2020 12:48 pm

bob sterman wrote: Thu Sep 17, 2020 12:10 pm In any case, plenty of studies have shown some COVID patients do have rhinorrhoea...

13.5% in this group of children...
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7327402/

16% in this group...
https://pubmed.ncbi.nlm.nih.gov/32725955/

Do either of those studies compare with the % of kids with those symptoms in the general, non-COVID infected population?

No they don't. I expect you're correct - the % with runny noses is not that different to the general population at this time of year.

Only posted them to show that people with positive COVID-19 tests CAN have runny noses. Not that it was particularly diagnostic.

Yes, sorry, I should have clarified that I agree with you that they do indeed make it clear that having a running nose is not some kind of magic indicator for not having COVID.

I was just wondering if there was any evidence for a runny nose being a symptom of COVID in children as I've heard several times that it's been reported as a concurrent symptom without anyone ever saying whether the runny-nose-rate was higher than would be expected in kids normally, or not.

Grumble wrote: Thu Sep 17, 2020 12:51 pm I’ve got a runny nose right now so I’m glad to hear that I haven’t got COVID.

Good. Could we meet up so I can catch what you've got so I'll be immune too?

Hmmm, I have chronic rhinitis - does that mean I can NEVER catch covid?

Mind you, it does mean disposable masks are the best option...

bagpuss wrote: Thu Sep 17, 2020 12:41 pm That does seem a tad dangerous.

I mean, certainly, the vast majority of people who currently have runny noses (I include myself, I currently feel like sh.t thanks to the bagkitten kindly sharing her cold with me) will not have COVID. But that doesn't mean that none of them will because, as you say, even if it's not a symptom, you could have a cold and COVID at the same time.

That said, I do think that there would be a benefit to amending the current testing advice. I know of quite a number of people who have (after some considerable effort) managed to get tests for their kids who are suffering from this same cold. In their cases, their kids have had a persistent cough and/or high temperature associated with it. Following current advice, that means either getting a test or self-isolating for 10 days, and 14 days for the rest of the family so since for some of them that would be 2 weeks without pay and 2 more weeks of their kids being off school, they've been making huge efforts to get tests. Even when the parents are 99% sure that it's a cold. So they're doing the right thing and doing what they're told, and then getting told off for clogging up the testing system. So yeah, testing advice needs changing, although I'm not sure that "look, if 50% of your child's fellow pupils are all suffering the same symptoms and you're currently sneezing your head off while you're reading this, then it's so unlikely that it's COVID that you can probably crack on with life as normal, unless other symptoms materialise" is quite the right wording. Obviously, the best thing would be to have enough testing capacity for everyone to have a test at the slightest reason, but that's a pipe dream right now.

I wondered if this is a situation where pooled testing would help. So if a class of kids has had 2 people testing negative and has 8 more kids waiting for tests, then those 8 most likely have a cold. If all their swabs are run as one sample, then we can save testing capacity and double check that one doesn't have covid with a snotty nose.

mediocrity511 wrote: Thu Sep 17, 2020 3:29 pm

bagpuss wrote: Thu Sep 17, 2020 12:41 pm That does seem a tad dangerous.

I mean, certainly, the vast majority of people who currently have runny noses (I include myself, I currently feel like sh.t thanks to the bagkitten kindly sharing her cold with me) will not have COVID. But that doesn't mean that none of them will because, as you say, even if it's not a symptom, you could have a cold and COVID at the same time.

That said, I do think that there would be a benefit to amending the current testing advice. I know of quite a number of people who have (after some considerable effort) managed to get tests for their kids who are suffering from this same cold. In their cases, their kids have had a persistent cough and/or high temperature associated with it. Following current advice, that means either getting a test or self-isolating for 10 days, and 14 days for the rest of the family so since for some of them that would be 2 weeks without pay and 2 more weeks of their kids being off school, they've been making huge efforts to get tests. Even when the parents are 99% sure that it's a cold. So they're doing the right thing and doing what they're told, and then getting told off for clogging up the testing system. So yeah, testing advice needs changing, although I'm not sure that "look, if 50% of your child's fellow pupils are all suffering the same symptoms and you're currently sneezing your head off while you're reading this, then it's so unlikely that it's COVID that you can probably crack on with life as normal, unless other symptoms materialise" is quite the right wording. Obviously, the best thing would be to have enough testing capacity for everyone to have a test at the slightest reason, but that's a pipe dream right now.

I wondered if this is a situation where pooled testing would help. So if a class of kids has had 2 people testing negative and has 8 more kids waiting for tests, then those 8 most likely have a cold. If all their swabs are run as one sample, then we can save testing capacity and double check that one doesn't have covid with a snotty nose.

I was having the same thought earlier. Would make sense for schools to coordinate this - first couple of kids in a class to get ill get a test. If it's negative then symptoms are communicated to parents with the message that tests should then only be sought for children who have different symptoms that fit COVID but not the cold.

Aitch wrote: Thu Sep 17, 2020 1:46 pm Hmmm, I have chronic rhinitis - does that mean I can NEVER catch covid?

Mind you, it does mean disposable masks are the best option...

I had chronic rhinitis for many years, but sorted it out with a nasal steroid spray. If I had known I was giving myself Covid I wouldn't have bothered.

mediocrity511 wrote: Thu Sep 17, 2020 3:29 pm I wondered if this is a situation where pooled testing would help. So if a class of kids has had 2 people testing negative and has 8 more kids waiting for tests, then those 8 most likely have a cold. If all their swabs are run as one sample, then we can save testing capacity and double check that one doesn't have covid with a snotty nose.

Reminds me - I was thinking I might try to economize on the cost of a private COVID-19 antibody test by mixing blood from various family members and sending it off for testing.

If one of us has antibodies - we've probably all been infected!

Or would our blood types attack each other?

bob sterman wrote: Thu Sep 17, 2020 8:17 pm

mediocrity511 wrote: Thu Sep 17, 2020 3:29 pm I wondered if this is a situation where pooled testing would help. So if a class of kids has had 2 people testing negative and has 8 more kids waiting for tests, then those 8 most likely have a cold. If all their swabs are run as one sample, then we can save testing capacity and double check that one doesn't have covid with a snotty nose.

Reminds me - I was thinking I might try to economize on the cost of a private COVID-19 antibody test by mixing blood from various family members and sending it off for testing.

If one of us has antibodies - we've probably all been infected!

Or would our blood types attack each other?

My family's probably wouldn't but ymmv

bob sterman wrote: Thu Sep 17, 2020 8:17 pm

mediocrity511 wrote: Thu Sep 17, 2020 3:29 pm I wondered if this is a situation where pooled testing would help. So if a class of kids has had 2 people testing negative and has 8 more kids waiting for tests, then those 8 most likely have a cold. If all their swabs are run as one sample, then we can save testing capacity and double check that one doesn't have covid with a snotty nose.

Reminds me - I was thinking I might try to economize on the cost of a private COVID-19 antibody test by mixing blood from various family members and sending it off for testing.

If one of us has antibodies - we've probably all been infected!

Or would our blood types attack each other?

Blood type reactions are an immune response (I think), which won't be a problem outside the body, other than certain cell culture conditions designed to keep the cells alive.

Pooled sample is a viable strategy that's being considered, for instance in the US. https://theconversation.com/group-testi ... ide-141579

So apparently the bloods don't even have to be related.

There was a case reported recently (in August) of a dorm block at a US college where they found a couple of cases after initially sampling wastewater from the whole block.

Bird on a Fire wrote: Fri Sep 18, 2020 12:58 am Pooled sample is a viable strategy that's being considered, for instance in the US. https://theconversation.com/group-testi ... ide-141579

So apparently the bloods don't even have to be related.

Yes - I can see that would work for PCR antigen testing. Going for a drive-through test I had considered bringing along some used tissues from family members and rubbing the swab all over them!

But I was wondering more about whether it would be OK for ELISA antibody testing?

bob sterman wrote: Fri Sep 18, 2020 9:54 am

Bird on a Fire wrote: Fri Sep 18, 2020 12:58 am Pooled sample is a viable strategy that's being considered, for instance in the US. https://theconversation.com/group-testi ... ide-141579

So apparently the bloods don't even have to be related.

Yes - I can see that would work for PCR antigen testing. Going for a drive-through test I had considered bringing along some used tissues from family members and rubbing the swab all over them!

But I was wondering more about whether it would be OK for ELISA antibody testing?

It should be feasible in principle (with caveats about how you're planning on combining samples - presumably not sticking the same needle into several people).

I would worry a bit about limits of detection though. RT-PCR is a signal-amplifying technique, so you can account for the dilution effect of combining donors (and maybe even estimate the # of positives in the pool). But ELISA doesn't work that way, so one +ve in a mixed pool will be harder to detect than in individual sampling.

There's also the point that the PCR is the "live" data that is needed for *immediate* decision making (both for the individual and at population level), so there's value in collecting it any way you can and as quickly as you can. Whereas the antibody tests are more an after-the-fact measure that is more useful for understanding where you were a couple of weeks/months back.

bob sterman wrote: Thu Sep 17, 2020 12:10 pm In any case, plenty of studies have shown some COVID patients do have rhinorrhoea...

Rhinorrhoea sounds like something you don't want a bout of if you run a zoo.

My cold has now developed into including a cough. I wouldn’t call it continuous, but I’m on the verge of thinking of getting a test. Still pretty sure it’s just a cold though.

Grumble wrote: Fri Sep 18, 2020 7:25 pm My cold has now developed into including a cough. I wouldn’t call it continuous, but I’m on the verge of thinking of getting a test. Still pretty sure it’s just a cold though.

'Getting a test'

Ever the optimist.

Mrs sTeamTraen and I have basically been on lockdown since March, give or take a visit from our kids, some socially distanced outdoor exercise classes, and eating out about once a week, always on terraces and sitting as far away as possible from everyone. But we've both managed to have two or three colds each. Whenever we cough we make extra efforts to produce some phlegm to prove it's not the dreaded dry cough. Mrs S also tends to lose her sense of smell when she gets a cold and I run a small fever quite easily, especially when it's hot, so we have had our share of "oh crap" moments.

I have not had a single cold since lockdown started. I have been extremely careful though. I wonder what the potential would be to stop transmission of all of these diseases. A little thought experiment: If everyone in the whole of the world just spontaneously went into lockdown, how long would it take for colds and flus and such to just die off? Assuming everybody did everything possible to isolate.

nezumi wrote: Sat Sep 19, 2020 12:42 pm I have not had a single cold since lockdown started. I have been extremely careful though. I wonder what the potential would be to stop transmission of all of these diseases. A little thought experiment: If everyone in the whole of the world just spontaneously went into lockdown, how long would it take for colds and flus and such to just die off? Assuming everybody did everything possible to isolate.

There's an xkcd (well, a What If) for that

https://m.imgur.com/a/RncmMXz