Diving post Covid

[Duke Dive Medicine]

What does "typically" mean in this case? Can we put some quantitative bounds on it?


How would we know that SARS-CoV-2 causes more long-term complications than HCoV-OC43, since the infectious disease experts have never done a direct before-and-after comparison of the lung damage caused by those two viruses, or other common cold viruses? The entire COVID-19 pandemic has been characterized by shoddy science, flawed assumptions, and a rush to hasty conclusions. A little more skepticism is warranted.


Really? Since HCoV-OC43 is just one of hundreds of endemic common cold viruses, and the specific virus makes little difference in the treatment protocol, clinicians almost never specifically test for it. I had a bad cold some years ago and was left with a persistent cough during any hard exertion that lasted for months. Was that from an HCoV-OC43 infection? Who knows? Did it cause lung damage? My doctor never ordered any respiratory tests or any imaging studies, and I didn't have previous baselines to compare against anyway. So also unknown and unknowable. In any case after the cough went away I resumed diving and sports training. So far my lungs haven't exploded.

The implicit null hypothesis here is that SARS-CoV-2 (COVID-19) is no more likely to cause lung damage (or other sequelae relevant to diving) than at least some other endemic common cold viruses. That null hypothesis could be false but I haven't seen sufficient evidence to reject it yet. So why are we treating this one virus as something special? Or conversely, have we been too casual about upper respiratory infections in general? Should we treat all such viruses the same and get evaluated for fitness to dive after every infection? Not a bad idea in principle, but I'm skeptical whether that would be a good use of scarce medical resources.

This sounds like a great research project for a young, highly motivated researcher. But, pulling back a little, there is no comparison between any specific common cold virus and SARS Co-V2. We're not in a cold pandemic right now. You need to compare apples to apples. If your cold virus caused widespread death, serious illness, and long-term respiratory effects, there would be enough of a public health concern to warrant specific guidance around returning to diving. We have specific guidance around COVID because of specific, known, long-term effects. And yes, really. If someone came to our clinic with residual respiratory sequelae from a viral illness, he or she would be evaluated based on his or her presenting symptoms, regardless of the organism.

I'm not going to engage you regarding COVID and science. Your vocabulary is great, but a responsible, erudite scientist would not make a blanket statement like "The entire COVID-19 pandemic has been characterized by shoddy science, flawed assumptions, and a rush to hasty conclusions." Those are the words of someone who has not been directly involved with the care of COVID patients or the science behind it.

Regarding your illness specifically, how do you know it was a cold? Was the organism cultured? If there's no solid evidence that it was a cold, how are you hanging an argument on it? Re your workup, I would defer to the provider who saw you in person, but in general, how do you know what was causing the cough? If you were concerned enough to be evaluated, how are you reassured that there was no residual damage without imaging (for which there certainly is a normal to compare against, if you're a radiologist) or pulmonary function testing, for which there is also a set of normal parameters to guide decision-making? I'm glad your lungs haven't exploded or done anything else radical, but you're an "n" of one.

All that said, I'm afraid I'm not understanding your overall point here. Are you asserting that there shouldn't be specific return-to-diving guidelines for post-COVID?

Best regards,
DDM

 

[Nick_Radov]

We have specific guidance around COVID because of specific, known, long-term effects. And yes, really. If someone came to our clinic with residual respiratory sequelae from a viral illness, he or she would be evaluated based on his or her presenting symptoms, regardless of the organism.

That's great and your clinic is among the best in the world, but it's not the reality for most other clinics. If a patient presents with a persistent cough a month after some unknown viral illness, most doctors won't do much more than listen with a stethoscope unless there are other significant symptoms or risk factors.

Regarding your illness specifically, how do you know it was a cold? Was the organism cultured? If there's no solid evidence that it was a cold, how are you hanging an argument on it?

As I'm sure you're aware, a "cold" is just a colloquial term for a collection of similar symptoms caused by hundreds of different viruses. Prior to the COVID-19 pandemic, if a patient presented with a sore throat, cough, muscle aches, sneezing, congestion, etc. then clinicians would usually diagnose that as a cold without trying to determine the specific infectious agent. In other words, if an illness has symptoms consistent with a cold then it's a cold. If it walks like a duck and quacks like a duck then it's a duck. We don't even have specific clinical assays for most of the hundreds of common cold viruses, so outside of a research study it's literally impossible to tell.

The symptoms of mild COVID-19 overlap significantly with many other common cold viruses. At this point in the pandemic, millions of patients have recovered from a SARS-CoV-2 infection without ever having been formally tested or diagnosed. If you had a bad cough a month ago was it COVID or something else? Hard to say. Do some of those patients have undetected lung damage that could impact diving fitness? Probably, but no one really knows. So it's logically inconsistent to apply a specific return-to-diving protocol only to patients with a COVID diagnosis.

Re your workup, I would defer to the provider who saw you in person, but in general, how do you know what was causing the cough? If you were concerned enough to be evaluated, how are you reassured that there was no residual damage without imaging (for which there certainly is a normal to compare against, if you're a radiologist) or pulmonary function testing, for which there is also a set of normal parameters to guide decision-making? I'm glad your lungs haven't exploded or done anything else radical, but you're an "n" of one.

There's no way to know for sure what was causing the cough. That's exactly my point. I was not reassured that there was no residual damage. Outside of a few leading clinics like your own, doing imaging studies and pulmonary function testing in such cases is not part of the standard care protocol (unless there are other significant symptoms or risk factors). The healthcare system is already strained so it seems unrealistic to expect that level of follow-up care.

Are you asserting that there shouldn't be specific return-to-diving guidelines for post-COVID?

I am asserting that there is not enough reliable evidence to justify having specific return-to-diving guidelines for post-COVID. If we're going to have guidelines then those should apply equally to all viral upper respiratory diseases, regardless of the specific virus. Maybe based on severity and duration of symptoms?

The reason I specifically called out the common cold virus HCoV-OC43 is that as a betacoronavirus it is genetically very similar to SARS-CoV-2.

Genomic and evolutionary comparison between SARS-CoV-2 and other human coronaviruses

Three highly pathogenic human coronaviruses can cause severe acute respiratory syndrome (SARS-CoV, SARS-CoV-2 and MERS-CoV). Although phylogenetic ana…

www.sciencedirect.com

It causes similar symptoms.

https://sfamjournals.onlinelibrary.wiley.com/doi/full/10.1111/1751-7915.13889

And it seems to have had a similar fatality rate when it first jumped to humans (although we don't have conclusive evidence there).

The enigma of the 1889 Russian flu pandemic: A coronavirus?

The “Russian flu”, which raged from 1889 to 1894, is considered as the first pandemic of the industrial era for which statistics have been collected. …

www.sciencedirect.com

But that's just one endemic virus, there are hundreds others. It's quite possible that at least some of those common cold viruses are causing hidden but significant lung damage in some patients. There hasn't been any kind of ongoing surveillance program, so we have no way of really knowing. Most people, including divers, lead sedentary lifestyles so they might not even notice a loss of lung function.

To draw an example from a different disease, up until 1984 we didn't know that H. pylori infection could cause stomach ulcers. So what else are we missing? Very few patients get frequent pulmonary workups so it's entirely possible that something surprising has been flying under the radar. Lots of unknown unknowns in this area.

 

[Duke Dive Medicine]

That's great and your clinic is among the best in the world, but it's not the reality for most other clinics. If a patient presents with a persistent cough a month after some unknown viral illness, most doctors won't do much more than listen with a stethoscope unless there are other significant symptoms or risk factors.

As I'm sure you're aware, a "cold" is just a colloquial term for a collection of similar symptoms caused by hundreds of different viruses. Prior to the COVID-19 pandemic, if a patient presented with a sore throat, cough, muscle aches, sneezing, congestion, etc. then clinicians would usually diagnose that as a cold without trying to determine the specific infectious agent. In other words, if an illness has symptoms consistent with a cold then it's a cold. If it walks like a duck and quacks like a duck then it's a duck. We don't even have specific clinical assays for most of the hundreds of common cold viruses, so outside of a research study it's literally impossible to tell.

The symptoms of mild COVID-19 overlap significantly with many other common cold viruses. At this point in the pandemic, millions of patients have recovered from a SARS-CoV-2 infection without ever having been formally tested or diagnosed. If you had a bad cough a month ago was it COVID or something else? Hard to say. Do some of those patients have undetected lung damage that could impact diving fitness? Probably, but no one really knows. So it's logically inconsistent to apply a post-COVID return-to-diving protocol only to patients with a COVID diagnosis.

There's no way to know for sure what was causing the cough. That's exactly my point. I was not reassured that there was no residual damage. Outside of a few leading clinics like your own, doing imaging studies and pulmonary function testing in such cases is not part of the standard care protocol (unless there are other significant symptoms or risk factors). The healthcare system is already strained so it seems unrealistic to expect that level of follow-up care.

I am asserting that there is not enough reliable evidence to justify having specific return-to-diving guidelines for post-COVID. If we're going to have guidelines then those should apply equally to all viral upper respiratory diseases, regardless of the specific virus. Maybe based on severity and duration of symptoms?

The reason I specifically called out the common cold virus HCoV-OC43 is that as a betacoronavirus it is genetically very similar to SARS-CoV-2.

Genomic and evolutionary comparison between SARS-CoV-2 and other human coronaviruses

Three highly pathogenic human coronaviruses can cause severe acute respiratory syndrome (SARS-CoV, SARS-CoV-2 and MERS-CoV). Although phylogenetic ana…

www.sciencedirect.com

It causes similar symptoms.

https://sfamjournals.onlinelibrary.wiley.com/doi/full/10.1111/1751-7915.13889

And it seems to have had a similar fatality rate when it first jumped to humans (although we don't have conclusive evidence there).

The enigma of the 1889 Russian flu pandemic: A coronavirus?

The “Russian flu”, which raged from 1889 to 1894, is considered as the first pandemic of the industrial era for which statistics have been collected. …

www.sciencedirect.com

But that's just one endemic virus, there are hundreds others. It's quite possible that at least some of those common cold viruses are causing hidden but significant lung damage in some patients. There hasn't been any kind of ongoing surveillance program, so we have no way of really knowing. To draw an example from a different disease, up until 1984 we didn't know that H. pylori infection could cause stomach ulcers. So what else are we missing? Very few patients get frequent pulmonary workups so it's entirely possible that something surprising has been flying under the radar. Lots of unknown unknowns in this area.

In sifting through this reply I think we might be in agreement on a lot of these points. COVID-19 was a big attention-grabber that shone a light on long-term sequelae of a particular viral respiratory illness, simply from the sheer volume of people it affected. Could a cold (and yes, I do know the definition) cause the same thing? Possibly, and nobody's looked at it because no so-called cold virus in recent memory has wrought the kind of havoc on the general population that COVID has. I wonder if the real thought-provoking question here might be (and I think this is what you're saying), do we need to look at the possibility of other respiratory viruses that have previously been considered benign causing the same long-term sequelae, and examine whether our criteria for returning to diving after COVID applies to those as well?

Best regards,
DDM

 

[Nick_Radov]

I wonder if the real thought-provoking question here might be (and I think this is what you're saying), do we need to look at the possibility of other respiratory viruses that have previously been considered benign causing the same long-term sequelae, and examine whether our criteria for returning to diving after COVID applies to those as well?

Yes, that is what I am saying.

 

[Duke Dive Medicine]

Yes, that is what I am saying.

I think that's a great question and deserves investigation.

Best regards,
DDM

 

[noserider]

I think that's a great question and deserves investigation.

Best regards,
DDM

It is a great question but perhaps we get a baseline with Covid results and then extend to other respiratory illnesses. Covid has wrecked havoc, claimed many lives and many are still suffering with symptoms.

Since starting this thread, I unfortunately got Covid and whilst quite mild did knock me out for a couple of weeks. 5 or 6 weeks after the infection, I attempted a 100 km bike ride with lots of climbing.

During the course of the ride my heart rate was on average about 20 bpm higher than similar pre covid ride and I had 90 minutes at a threshold level and 49 minutes at anerobic levels with my heart rate topping out at a level I had not seen since I was in my 30's and my average speed was down by about 20%. So Covid has had an affect on my general fitness and thus I think it is right be concerned about fitness levels post covid when diving.

Luckily my fitness is returning quite quickly and whilst I have lost some speed my HR is back inline with pre covid levels

 

[kinoons]

In sifting through this reply I think we might be in agreement on a lot of these points. COVID-19 was a big attention-grabber that shone a light on long-term sequelae of a particular viral respiratory illness, simply from the sheer volume of people it affected. Could a cold (and yes, I do know the definition) cause the same thing? Possibly, and nobody's looked at it because no so-called cold virus in recent memory has wrought the kind of havoc on the general population that COVID has. I wonder if the real thought-provoking question here might be (and I think this is what you're saying), do we need to look at the possibility of other respiratory viruses that have previously been considered benign causing the same long-term sequelae, and examine whether our criteria for returning to diving after COVID applies to those as well?

Best regards,
DDM

I think the question at hand is when the currently know existing corona, rhino, and parainfluenza virus subtypes made the jump to humans, were similar pandemics the results until the human immune system learned that virus?

Because medical science has only been able to identify and type specific a virus for less than 75 years, it’s very hard to tell what the history was for prior infections and their severity. We can take a guess from the Spanish flu and smallpox that a novel virus can wreck havoc on a population, but even still that’s relatively recent history.

My $0.50 guess - prior to good record keeping there were similar pandemics from the currently endemic set of “cold” viruses when that particular virus wasn’t endemic. Long lasting symptoms from a viral infection is a know thing, we’re just seeing “more” due to the volume of folks getting sick over the last 2-3 years; the ratio is actually closer to expected rate of post viral illness.

But as has been noted, there is certianly opportunity for more research in this space.

 

[Nick_Radov]

I think the question at hand is when the currently know existing corona, rhino, and parainfluenza virus subtypes made the jump to humans, were similar pandemics the results until the human immune system learned that virus?

There is strong circumstantial evidence that this is exactly what happened with HCoV-OC43 in 1889. See the article links I posted above for details. Matthew Yglesias has also written a pretty good layman's summary.

Covid-1889

Was the "Russian flu" caused by a zoonotic coronavirus crossover?

www.slowboring.com

But it's unlikely we'll ever be able to conclusively answer your question.

 

[kinoons]

There is strong circumstantial evidence that this is exactly what happened with HCoV-OC43 in 1889. See the article links I posted above for details. Matthew Yglesias has also written a pretty good layman's summary.

Covid-1889

Was the "Russian flu" caused by a zoonotic coronavirus crossover?

www.slowboring.com

But it's unlikely we'll ever be able to conclusively answer your question.

Thanks for the links, I’ll give them a look and see what else I can find; layman summaries are useful, but I’m in the medical community as well so I’m versed in reading primary resources.

 

[Nick_Radov]

Thanks for the links, I’ll give them a look and see what else I can find; layman summaries are useful, but I’m in the medical community as well so I’m versed in reading primary resources.

Just so you don't get the wrong impression, let me be clear that I'm not in the medical community myself. More like "medical community adjacent". So don't take anything I write on medical topics too seriously.