[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