[EvaH (OP)]

David asks:

With regards to COVID virus mutations, is it likely that the same starting point virus will, during the course of its progression via transmission and mutation, give rise to the same mutations irrespective of where it is in the world or is there likely to be a genetic influence from infected hosts that contributes?

What do you think?

[alancalverd]

The evidence suggests that mutations are entirely random. The success of any mutation clearly depends on its viability and infectivity, which will possibly vary between host populations.

A glaring oddity seems to be the apparent vulnerability of Asian  descendants living in the UK compared with the surprisingly low infection rates in India.

[charles1948]

The evidence suggests that mutations are entirely random. The success of any mutation clearly depends on its viability and infectivity, which will possibly vary between host populations.

A glaring oddity seems to be the apparent vulnerability of Asian  descendants living in the UK compared with the surprisingly low infection rates in India.

Do you think that the "surprisingly low" infection rates reported in India, and especially in China , are reliable?

In these Eastern countries, a lot of emphasis is placed on "saving face".  Mightn't this lead to a tendency to "adjust" the statistics in a favourable direction?

[evan_au]

COVID virus ... give rise to the same mutations irrespective of where it is in the world

There are about 30,000 RNA bases in the SARS-COV2 virus.
- You can expect 1 or 2 RNA mutations per month, in each chain of infection
- This counts only the mutations that are infectious, and can persist in the community
- There are undoubtedly many other mutations which are not infectious (or less infectious), and die out.

There are currently slightly over 100 million infected people, worldwide.

100 million infected people and 30,000 RNA bases tells you that every day, every one of those RNA bases is mutated to every one of the 3 other possibilities at each location, somewhere in the world.
- So the same mutations do keep occurring, all the time
- What allows the strains to be distinguished is that a second mutation is unlikely to change the first mutation back, and is more likely to affect some other point in the RNA.
- The number of possible combinations for 2 mutations is 30,000 x 30,000 = 900 million. This won't happen every day, since there are only 100 million infections, worldwide.
- The number of possible combinations for 3 mutations is 30,000 x 30,000 x 30,000 = 3,000 billion. This allows strains to be fairly readily identified.
- After 12 months, most strains have accumulated around 15 mutations since the original Wuhan strain(s)

The risk with high levels of ongoing infection is that new strains (combinations of mutations) are appearing at a rapid rate.
- Some of these strains will be sufficiently different that they will allow re-infection of people who previously suffered from a different strain
- And also the possibility that they will allow infection of vaccinated individuals.
- The variants of most concern are those that affect the spike protein, as that is the target of all the vaccines

[set fair]

The evidence suggests that mutations are entirely random. The success of any mutation clearly depends on its viability and infectivity, which will possibly vary between host populations.

For example non pharmacuetical interventions, particularly lockdowns favour more transmissible variants. Whereas in Brazil where there is much less of this and a high proprtion of people have been infected once already, the evolutionary pressure favours a variant which can escape immunity. This, presumeably, will be the case here in the UK as vaccination continues.