[Genuine Realist]

There is some evidence that the Covid-19 virus mutated sometime in January or early February. There are a lot of links on this - I'll content myself with one - https://www.statnews.com/2020/05/26/new-...o-stop-it/.

I'll leave the medical and biological implications to others. To me, it's the effect on the as yet unwritten history here that interests me.

Could it be that there are no villains here? That the relatively relaxed attitude of the Chinese at the outset was based on their experience with a form of Covid-19 that was relatively non-transmissable? That their claim that they were infected by a European or American version has some legitimacy? That the optimism of the WHO (echoed by Trump) in January also reflected that earlier experience? That what changed in February, first noticed in Italy, was a far more virulent version of Covid-19? 

That everyone's statements in real time were accurate? That the reality of the virus changed?

It's an interesting question, unresolvable at this time.

[Genuine Realist]

There is some evidence that the Covid-19 virus mutated sometime in January or early February. There are a lot of links on this - I'll content myself with one - https://www.statnews.com/2020/05/26/new-...o-stop-it/.

I'll leave the medical and biological implications to others. To me, it's the effect on the as yet unwritten history here that interests me.

Could it be that there are no villains here? That the relatively relaxed attitude of the Chinese at the outset was based on their experience with a form of Covid-19 that was relatively non-transmissable? That their claim that they were infected by a European or American version has some legitimacy? That the optimism of the WHO (echoed by Trump) in January also reflected that earlier experience? That what changed in February, first noticed in Italy, was a far more virulent version of Covid-19? 

That everyone's statements in real time were accurate? That the reality of the virus changed?

It's an interesting question, unresolvable at this time.

[burger]

I don't have time or patience to explain thoroughly, but you have completely misunderstood the point of that article.  There is no evidence for a more transmissible strain.  "Mutation" here simply means that the virus' RNA changed over time.  Most such changes are meaningless for the lethality or infectiousness of the virus.

You should delete this.

[burger]

I don't have time or patience to explain thoroughly, but you have completely misunderstood the point of that article.  There is no evidence for a more transmissible strain.  "Mutation" here simply means that the virus' RNA changed over time.  Most such changes are meaningless for the lethality or infectiousness of the virus.

You should delete this.

[BostonCard]

SARS-CoV-2 is an RNA virus.  RNA viruses mutate, because the machinery to reproduce them is flawed.  In fact, even complex organisms (humans) have mutations.  Most mutations are silent and of no relevance.

There is some concern, derived from experience with influenza, but not proven with SARS-CoV-2, that mutations can help the virus escape immunologic protection.  "Antigenic drift", in influenza means that there variation in the two major proteins that the body detects: hemagglutinin and neuraminidase reduce the ability of patients to recognize the virus, which means patients can be re-infected with influenza (though usually less severe than if it is a complete new strain), which is why you need a new vaccine every year.

With regards to whether there are multiple strains with differential lethality or infectiousness, none of this has been proven.  Here's a blunt blog that makes the point:

https://www.virology.ws/2020/05/07/there...ars-cov-2/

When SARS-CoV-2 is isolated from a COVID-19 patient, that virus is called an isolate. The origin of the term is clear: the virus has been isolated from a patient.

These virus isolates are all the same strain of SARS-CoV-2. They are not different strains, even if they have changes in their genome sequences. A virus strain is an isolate with a different biological property, such as binding to a different receptor, or having a distinctly different stability at higher temperatures, to give just two of many possible examples.

There is only one strain of SARS-CoV-2. The first virus isolate, taken from a Wuhan patient in December 2019, is the same strain as the most recent isolate taken anywhere else in the world in May 2020. So far no one has shown that any of these virus isolates differ in any fundamental property.

BC

[BostonCard]

SARS-CoV-2 is an RNA virus.  RNA viruses mutate, because the machinery to reproduce them is flawed.  In fact, even complex organisms (humans) have mutations.  Most mutations are silent and of no relevance.

There is some concern, derived from experience with influenza, but not proven with SARS-CoV-2, that mutations can help the virus escape immunologic protection.  "Antigenic drift", in influenza means that there variation in the two major proteins that the body detects: hemagglutinin and neuraminidase reduce the ability of patients to recognize the virus, which means patients can be re-infected with influenza (though usually less severe than if it is a complete new strain), which is why you need a new vaccine every year.

With regards to whether there are multiple strains with differential lethality or infectiousness, none of this has been proven.  Here's a blunt blog that makes the point:

https://www.virology.ws/2020/05/07/there...ars-cov-2/

When SARS-CoV-2 is isolated from a COVID-19 patient, that virus is called an isolate. The origin of the term is clear: the virus has been isolated from a patient.

These virus isolates are all the same strain of SARS-CoV-2. They are not different strains, even if they have changes in their genome sequences. A virus strain is an isolate with a different biological property, such as binding to a different receptor, or having a distinctly different stability at higher temperatures, to give just two of many possible examples.

There is only one strain of SARS-CoV-2. The first virus isolate, taken from a Wuhan patient in December 2019, is the same strain as the most recent isolate taken anywhere else in the world in May 2020. So far no one has shown that any of these virus isolates differ in any fundamental property.

BC

[Genuine Realist]

No, this is a flat out speculation. The possibility interests me. 

It does account for the confused and contradictory public attitudes during January and February.

Of course  I am not going to delete the thread. The link is obviously not supportive, but it does discuss the explorations into mutations. The fact that the initial hypothesis of the introduction of the virus into Washington is interesting.

[Genuine Realist]

No, this is a flat out speculation. The possibility interests me. 

It does account for the confused and contradictory public attitudes during January and February.

Of course  I am not going to delete the thread. The link is obviously not supportive, but it does discuss the explorations into mutations. The fact that the initial hypothesis of the introduction of the virus into Washington is interesting.

[akiddoc]

I heard an interview of a coronavirus researcher the other day who says that Covid-19, unlike other RNA viruses, has a gene that causes a much lower mutation rate than the usual. I'll try to see if I can find a written source.

[akiddoc]

I heard an interview of a coronavirus researcher the other day who says that Covid-19, unlike other RNA viruses, has a gene that causes a much lower mutation rate than the usual. I'll try to see if I can find a written source.

[Goose]

I heard an interview of a coronavirus researcher the other day who says that Covid-19, unlike other RNA viruses, has a gene that causes a much lower mutation rate than the usual. I'll try to see if I can find a written source.

I have also seen that article. https://www.nature.com/articles/d41586-020-01315-7
COVID-19 actually has an "RNA Repair" mechanism, which attempts to "fix" any mutations. Like the human DNA repair mechanism, it isn't perfect, but it does reduce the probability of mutation.

[Goose]

I heard an interview of a coronavirus researcher the other day who says that Covid-19, unlike other RNA viruses, has a gene that causes a much lower mutation rate than the usual. I'll try to see if I can find a written source.

I have also seen that article. https://www.nature.com/articles/d41586-020-01315-7
COVID-19 actually has an "RNA Repair" mechanism, which attempts to "fix" any mutations. Like the human DNA repair mechanism, it isn't perfect, but it does reduce the probability of mutation.

[magnus]

This new information is more consistent with the fact that WA traced 60 close contacts of WA1 and found not a single additional case.

[magnus]

This new information is more consistent with the fact that WA traced 60 close contacts of WA1 and found not a single additional case.

[Genuine Realist]

This new information is more consistent with the fact that WA traced 60 close contacts of WA1 and found not a single additional case.

I don't comment on areas in which I have no particular expertise. But I will speculate and invite comment.

I was curious where the notion arose that are two different strains of Covid-19. I found this interesting article on WedMd, obviously not the most prestigious site around, but still . . .https://www.webmd.com/lung/coronavirus-strains#1

On the second page, under the heading 'Second Coronavirus STRAIN' (sic, my emphasis), you will notice a discussion of two separate STRAINS, a word I am emphasizing because BC indicates it was a term of art. One is demoninated 'L', the other 'S', why I don't know, except that it is almost certainly not a homage to 'Laverne and Shirley'. (RIP Penny Marshall.) They have different characteristics and one MAY be more transmissable than the other.

I won't write more, as I have nothing worthwhile to add. But I would hope for comment from those that do.

[Genuine Realist]

This new information is more consistent with the fact that WA traced 60 close contacts of WA1 and found not a single additional case.

I don't comment on areas in which I have no particular expertise. But I will speculate and invite comment.

I was curious where the notion arose that are two different strains of Covid-19. I found this interesting article on WedMd, obviously not the most prestigious site around, but still . . .https://www.webmd.com/lung/coronavirus-strains#1

On the second page, under the heading 'Second Coronavirus STRAIN' (sic, my emphasis), you will notice a discussion of two separate STRAINS, a word I am emphasizing because BC indicates it was a term of art. One is demoninated 'L', the other 'S', why I don't know, except that it is almost certainly not a homage to 'Laverne and Shirley'. (RIP Penny Marshall.) They have different characteristics and one MAY be more transmissable than the other.

I won't write more, as I have nothing worthwhile to add. But I would hope for comment from those that do.

[fullmetal]

Coronaviruses are unsegmented RNA viruses, where as the flu virus is a segmented RNA virus.  Those segments in the flu virus allow for a higher mutation rate and also more substantial mutations.  

I highly doubt that any coronavirus mutations (on the order of one or few base pairs per mutation) have had a substantial effect on the covid severity.  The what-if nature of these mutation questions has about a single-digit percentage likelihood of relevance, and any non-expert speculation would seem to be a waste of time.

[fullmetal]

Coronaviruses are unsegmented RNA viruses, where as the flu virus is a segmented RNA virus.  Those segments in the flu virus allow for a higher mutation rate and also more substantial mutations.  

I highly doubt that any coronavirus mutations (on the order of one or few base pairs per mutation) have had a substantial effect on the covid severity.  The what-if nature of these mutation questions has about a single-digit percentage likelihood of relevance, and any non-expert speculation would seem to be a waste of time.

[BostonCard]

I think it's because of loose use of language.  I myself have referred to them as viral "strains", but as the virologist makes clear, different strains should have measureably different properties, not merely genetic differences.

Uptodate simply refers to them as two different types of virus:

In a phylogenetic analysis of 103 strains of SARS-CoV-2 from China, two different types of SARS-CoV-2 were identified, designated type L (accounting for 70 percent of the strains) and type S (accounting for 30 percent) [9]. The L type predominated during the early days of the epidemic in China, but accounted for a lower proportion of strains outside of Wuhan than in Wuhan. The clinical implications of these findings are uncertain.

BC

[BostonCard]

I think it's because of loose use of language.  I myself have referred to them as viral "strains", but as the virologist makes clear, different strains should have measureably different properties, not merely genetic differences.

Uptodate simply refers to them as two different types of virus:

In a phylogenetic analysis of 103 strains of SARS-CoV-2 from China, two different types of SARS-CoV-2 were identified, designated type L (accounting for 70 percent of the strains) and type S (accounting for 30 percent) [9]. The L type predominated during the early days of the epidemic in China, but accounted for a lower proportion of strains outside of Wuhan than in Wuhan. The clinical implications of these findings are uncertain.

BC