Fair enough, I agree it's a stretch.
Other than our general risk tolerance / preference, I think the main place we diverge here is our assessment of vaccine efficacy. You're sure there's going to be a shit-load of breakthrough infections post-booster, and if that is the case then my entire argument is at least redundant, and probably stupid. Inevitably booster + mild infection would be better than 2nd dose + mild infection.
I'm much more optimistic that the booster will prevent infection in the short-term. I've just not seen the evidence that the risk of breakthrough infection post-booster is that high. We'll definitely find out soon!
Not really, mostly for practical reasons. From the PHE study (pages
6-8) we saw immunity start to wane 10 weeks after the second dose, which echoes what they're saying
now about the booster. We don't have much data after 10 weeks as the booster roll-out started properly in the beginning of October, 12 weeks ago.
While that makes for an interesting headline, it doesn't tell us much. Even though the level of protection against symptomatic disease started to drop 10 weeks after the 2nd dose, it didn't drop by much: for AZ it dropped from 65% to 60%, for Pfizer it dropped from 90% to 80%. And more importantly, protection against hospitalisation hardly dropped at all: from 95% to 90% for AZ, and from 98% to 96% for Pfizer (or thereabouts). Or as PHE put it:
When you get to 6 months the declines were more substantial after dose 2, and no-one in the UK has been boosted for that long. Israel might have some data on that but I've not seen any.
One other thing worth mentioning about the "immunity begins to wane after 10 weeks" headline is that we know immunity
wanes quicker among more vulnerable populations, and it's the more vulnerable populations that got boosted first. So we should assume it'll wane slower for the general population than whatever the waning is now. And given how much the booster multiplied the number of antibodies, it's waning from a much higher bar so it seems reasonable to assume protection will last longer post-booster than post-dose 2. Even with Omicron's capacity for immune escape, from what I can tell. EDIT: Maybe not with Omicron.
It's worth saying that immunity isn't really a binary thing either, so there won't be a point that immunity will last until. There'll likely be some level of immune response for years to come from that second vaccine dose - that's what they saw post-MERS trials - it just becomes less effective as the volume of immune first responders (antibodies, B-cells, T-cells) declines. The dose of infection we get varies so a low-dose infection can still be fought off by a low-dose immune response.
The figures about waning immunity look at the average person with the average dose of infection, which is useful at the population level but less useful at the individual level. In other words we shouldn't think about those timings as cut-off points for when we suddenly stop being immune to covid, it's more complicated than that.
