[set fair (OP)]

There seem to be two seperate factors.

1) Variants are escaping our immunity (by the way anyone know why virologists don't say "are becoming resistant"?). One of the common coronaviruses changes enough to reinfect after 2 years and changes beyond recognition in 8 years. Can we plan for this or is by gosh and by gum all we can do?

2) Waning immunity. However important t-cells may be, they are hard to measure, so it looks like we are left with antibodies as markers of protection. An alternative might be to measure the time between fisrt infection and reinfection - a bit difficult when we undertested by about an order of magnitude in the first wave. We could say the variants of concern started emerging about 6 months after the first wave and this must have occurred in reinfected people. Then we would need to keep the interval between jabs to no more than 4 or 5 months.

Personaly I favour 4 or 5 months as a maximum - I think it would be just dumb to have another wave and another lockdown starting in late summer or the autumn because we didn't boost soon enough. I just wonder why we aren't being told what the state of planning is?

[evan_au]

the variants of concern ...must have occurred in reinfected people

You might have this backwards...
- The variants will appear about every 2-3 weeks in the chain of infected people.
- When the variant differs sufficiently from the original that it is no longer recognizable, then people will get reinfected
- The more people that are infected at once, the more chains of infection there will be, and the greater number of variants generated. This increases the chance that a sufficiently different variant will appear

There is another class of high-risk patients: Those with a chronic COVID-19 infection.
- These patients are probably in hospital, being treated with our most effective treatments (which are, unfortunately, few in number at this time)
- The virus is likely to develop resistance to our most advanced treatments.
- If these variants escape, that could lead to a very serious outbreak

[set fair (OP)]

the variants of concern ...must have occurred in reinfected people

You might have this backwards...
- The variants will appear about every 2-3 weeks in the chain of infected people.
- When the variant differs sufficiently from the original that it is no longer recognizable, then people will get reinfected
- The more people that are infected at once, the more chains of infection there will be, and the greater number of variants generated. This increases the chance that a sufficiently different variant will appear

There is another class of high-risk patients: Those with a chronic COVID-19 infection.
- These patients are probably in hospital, being treated with our most effective treatments (which are, unfortunately, few in number at this time)
- The virus is likely to develop resistance to our most advanced treatments.
- If these variants escape, that could lead to a very serious outbreak

You make reasonable points but the variants of concern - the ones which which have shown some resistance by loosing / changing epitopes all started appearing 6 months after the first wave. This is astrong indication that it is the immune escape is driven by the re-infected with waning immunity.

[Bored chemist]

(by the way anyone know why virologists don't say "are becoming resistant"?).

I wasn't aware that any of the new variants had "become resistant".
In most cases the immune system knocks back the infection in much the same way, regardless of the particular variant you catch.

[set fair (OP)]

OK Evan you have more than reasonable points.

As far as a build up of mutations in the normal course of things: perfectly possible, the gnomic lineage is both very large and incomplete (except perhaps in Denmark), so it almost certainly can neither be proved nor disproved as the origin of the VoCs.

The long term infection of an immune-compromised person is also quite feasible as the origin.

But I still think that people infected in the first wave are are the drivers of these variants ie they are responsible for its mushrooming. Their waning antibodies maybe enough to stop a repeat infection of the same or similar variant which initially infected them. But not enough to stop the new variant, against which some of their antibodies are rendered useless by mutations.

If reinfected people with waning antibodies were not driving the mutation, one would have to explain why the VoCs started blooming 6 months after the first wave and not in early summer or during the first wave and why at the same time. They may have arisen earlier  but they all increased in prevalence at around the same time.

So I think boosters 3 times a year to include the latest variants is the way to go, which will mean we need more vaccine manufacturing capacity.

It is quite possible that the new variant only appears more infectious- ie it isn't intrinsically more infectious but it spreads faster because there is a bigger pool of people to infect. That pool would have been almost everyone when it first arose whereas the pool that the earlier variant could infect was smaller - everyone who hadn't been previously infected.

[set fair (OP)]

India's first wave was later than Europe anf the Indian variant followed the trend - blooming six months after the first wave.

[evan_au]

Personaly I favour 4 or 5 months as a maximum (to be revaccinated)

All the manufacturers need to be preparing a polyvalent vaccine. And new vaccinations need to switch to the polyvalent vaccine as soon as it has passed safety tests (efficacy could be tested via antibodies, since we now know that is a good indicator of prompt protection).

Before you spend a lot of effort in getting a 3rd vaccine into yourself, it is important to ensure that the countries with high infection rates get vaccinated, to reduce the generation of new variants.

[CliffordK]

Personaly I favour 4 or 5 months as a maximum (to be revaccinated)

All the manufacturers need to be preparing a polyvalent vaccine. And new vaccinations need to switch to the polyvalent vaccine as soon as it has passed safety tests (efficacy could be tested via antibodies, since we now know that is a good indicator of prompt protection).

Before you spend a lot of effort in getting a 3rd vaccine into yourself, it is important to ensure that the countries with high infection rates get vaccinated, to reduce the generation of new variants.

Precisely.  I wish there was an option of a multi-valent vaccine available for the second dose (including the original spike protein), and I'd been right on it, even without long efficacy testing.

Enough people that have either been vaccinated,or have the vaccination in progress are getting infected that it may stimulate evolution of vaccine resistant strains.  This is one of the problems with the slow vaccine rollout coupled with anti-vaxxers. 

I'm not convinced that following a monumental effort to get the first and second doses out that we'll be prepared for rolling out a third dose in a timely manner.