How many mutations does coronavirus experience per year?

[Job 33:6]

See the post title. Does anyone know? Is the number dependent upon the population of the virus or of it has a host?

Thanks,

 

[sfs]

See the post title. Does anyone know?

26 mutations per year (from nextstrain.org).

Is the number dependent upon the population of the virus or of it has a host?

The number of mutations present in the population depends on the population size; the rate quoted above is the rate that each lineage of the virus accumulates. That's all assuming that the virus is being transmitted normally -- if you put a sample in the freezer, it won't mutate while it's there.

 

[Job 33:6]

26 mutations per year (from nextstrain.org).

The number of mutations present in the population depends on the population size; the rate quoted above is the rate that each lineage of the virus accumulates. That's all assuming that the virus is being transmitted normally -- if you put a sample in the freezer, it won't mutate while it's there.

You say that the number is with respect to each lineage. Can we estimate how many lineages exist? Or is that an absurd question?

 

[sfs]

You say that the number is with respect to each lineage. Can we estimate how many lineages exist? Or is that an absurd question?

It's not a very useful question. Every infected individual hosts a distinct lineage (a distinct branch of the viral tree), and in fact every copy of the virus in every person starts a new lineage (most of which will quickly die out, of course). The number of genome sites that differ between two people's viruses is the number of mutations that have occurred since they shared a common ancestor (ignoring multiple mutations at the same site.)

 

[Job 33:6]

It's not a very useful question. Every infected individual hosts a distinct lineage (a distinct branch of the viral tree), and in fact every copy of the virus in every person starts a new lineage (most of which will quickly die out, of course). The number of genome sites that differ between two people's viruses is the number of mutations that have occurred since they shared a common ancestor (ignoring multiple mutations at the same site.)

Thanks.

What if I asked...what the likelihood is, in a given year, that a virus as deadly as covid-19 would evolve (from a covid-19 lineage)? If a vaccine is made for covid-19, could we guess how long the vaccine would be useful before covid-19 would evolve and return to be deadly again? And could mutation rate be used to estimate this?

 

[A_Thinker]

.

 

[SkyWriting]

Thanks. What if I asked...what the likelihood is, in a given year, that a virus as deadly as covid-19 would evolve (from a covid-19 lineage)? If a vaccine is made for covid-19, could we guess how long the vaccine would be useful before covid-19 would evolve and return to be deadly again? And could mutation rate be used to estimate this?

We haven't figured out if a mask is good or not. So No, no and no.

 

[Tanj]

You say that the number is with respect to each lineage. Can we estimate how many lineages exist? Or is that an absurd question?

Go to the site @sfs linked, change the view from clock to rectangular in the left hand pane.

Thanks.

What if I asked...what the likelihood is, in a given year, that a virus as deadly as covid-19 would evolve (from a covid-19 lineage)?

We have absolutely no idea. Estimating new outbreaks, even for existing viruses, is completely beyond us.

If a vaccine is made for covid-19, could we guess how long the vaccine would be useful before covid-19 would evolve and return to be deadly again?

No. More importantly, it's very likely, from what we know of other coronaviruses, that immunity is short lived, lasting about a year or so. Which is to say the virus doesn't need to mutate, you just have to not get your yearly booster.

And could mutation rate be used to estimate this?

No.

The bottom line is we have no real way of determining which mutations increase pathogenicity and which ones are just there for the ride.

ETA I will take the opportunity to point out that most US cases came from a small number of entries from China, and most Australian cases came from the US.

 

[Jok]

Can anyone answer a question that I have? I know that the 2nd/mutated wave of Spanish Flu was much deadlier than the first, but was the lethality of the 2nd wave mainly people who never caught the first strain/wave? If you catch a first strain of a virus and develop defenses against it, even though a mutated strain is different would your survival of the first strain make you better equipped to take on the 2nd strain compared to another person who never got the first strain (all things being equal between the two people)? I’m assuming that you would be better off than the other person who never got the 1st strain, since even though it’s a mutated strain it still must be recognizable to your system because it’s related. Am I right or wrong on that assumption? Thanks.

 

[Tanj]

Can anyone answer a question that I have? I know that the 2nd/mutated wave of Spanish Flu was much deadlier than the first, but was the lethality of the 2nd wave mainly people who never caught the first strain/wave?

Spanish flu - Wikipedia
The fact that most of those who recovered from first-wave infections had become immune showed that it must have been the same strain of flu.

If you catch a first strain of a virus and develop defenses against it, even though a mutated strain is different would your survival of the first strain make you better equipped to take on the 2nd strain compared to another person who never got the first strain (all things being equal between the two people)?

Depends on the virus. There's no easy answer. Some viruses do not trigger life long immunity either. Others exist in so many forms that there's no way to be immune to all of them.

Flu is unusual in that it's genome contains 8 segments. Most viruses have 1. So if someone, or some animal, gets infected with 2 completely different strains, a completely new virus can arise that no creature on the planet has seen.

 

[SkyWriting]

Can anyone answer a question that I have? I know that the 2nd/mutated wave of Spanish Flu was much deadlier than the first, but was the lethality of the 2nd wave mainly people who never caught the first strain/wave? If you catch a first strain of a virus and develop defenses against it, even though a mutated strain is different would your survival of the first strain make you better equipped to take on the 2nd strain compared to another person who never got the first strain (all things being equal between the two people)? I’m assuming that you would be better off than the other person who never got the 1st strain, since even though it’s a mutated strain it still must be recognizable to your system because it’s related. Am I right or wrong on that assumption? Thanks.

Maybe.

 

[ruthiesea]

See the post title. Does anyone know? Is the number dependent upon the population of the virus or of it has a host?

Thanks,

Deadly viruses tend to evolve to less deadly forms. That way they can continue to use the host. When the host dies the virus dies (eventually) unless it is picked up by another host. It is believed that this is what helped stop the Spanish flu.

Another factor is that, usually, a survivor is immune from again becoming diseased. Also, of course, as in the case of the Black Plague, the disease just runs out of a susceptible population.

 

[sfs]

Deadly viruses tend to evolve to less deadly forms.

This virus is already not very deadly for most people who get it, so I don't see strong selection pressure to become less virulent. Hope it does, though. . .

 

[Radagast]

See the post title. Does anyone know? Is the number dependent upon the population of the virus or of it has a host?

If it's like SARS, it averages up to about 50 base pair mutations per year, I believe.

Many of those mutations make the virus non-viable. Some make it more deadly. Some make it less deadly.

 

[Radagast]

Deadly viruses tend to evolve to less deadly forms. That way they can continue to use the host. When the host dies the virus dies (eventually) unless it is picked up by another host. It is believed that this is what helped stop the Spanish flu.

Of course, the Spanish flu appeared because of exactly the opposite thing: an ordinary flu virus mutating to become more deadly.