In reply to bruxist:
I think there's one bit of your approach to this that I disagree on, so I'll dig in to that first:
> We wouldn't normally use herd immunity primarily to protect a healthcare system from overload; rather, we would hope to reach a threshold at which the unprotected (the elderly, the immunocompromised, the generally vulnerable) are protected from the likelihood of contracting a disease in the first place, because it cannot spread among the rest of the population.
I think the conventional idea of "herd immunity" has been out of the window since the Alpha variant came along; this disease is just too transmissive for elimination through very high uptake with current vaccine efficacies. We can't achieve that level of herd immunity, certainly not with the fraction of people not engaging with vaccination.
The future with this virus to me looks like periodic re-infection as antibodies fade, sometimes compounded by genetic drift breaking the neutralising power of antibodies faster.
- Herd immunity no longer protects the vulnerable from this, because people are going to get repeatedly re-exposed, and their protection against infection fades over time. The re-infection rate goes on to be determined by the immune wanning timescales, not the level of immune protection in the population.
- We could aggressively vaccinate every year to keep transmission down, but it's not possible to predict the next variant, and it takes time from emergence to validation and at scale production of a vaccine. I think it's only by the skin of our teeth that a 3rd dose of current vaccines has efficacy against infection for Omicron - it's taking an incredibly high antibody level to deliver what we got for much less with Delta; and that level is going to fade.
- There'll be some sort of phase-locking behaviour to seasonality most likely. Properly timed boosters that track the genetics, or that rely on producing very high antibody levels to overcome poor binding affinity when not up-to-date with the variant (where we are now with omicron) cold give brief periods of protection slowing down transmission, which will help safeguard the most vulnerable through the peak periods in the infectious cycle (likely beating to the seasonal drum?). New MAB cocktails could do likewise for those with poor immune response.
- The important immunity here is not protection against infection/transmission but protection against severe disease. This is where we are with "common cold" causing viruses, including a coronavirus (OC43) that may have made its entrance in to our nuisance-level viral pantheon through a pandemic. As far as I can divine this is what policy is actually taking us towards.
For a thought experiment, imagine we stayed in global lockdown for a decade. Omicron breaks between 15% and 30% of various T-cell epitopes (pattern recognition to target the virus) from the current vaccine. That's changes that have happened in the 21 months since vaccination work started. Over a decade we might see almost no remaining T-cell immunity given ongoing mutation. When we come out of that lockdown, there's no T-cell affinity left and when it lands, it's a brand new pandemic.
- For a stable endemic situation, the virus - or well matched, broad spectrum vaccines - have to go in to people to re-stimulate and refresh the T-cell immunity, so that it tracks variations over time.
- The longer we take to do this - with all the unpleasant consequences it involves - the worse the intangible but rising pandemic potential risk.
> I'm assuming that was the logic behind the July strategy - spread now, lower the ability to spread later.
To a point yes; it should lower the spread during the winter months, but then that ability to spread recovers as antibodies fade - but enduring protection from severe illness remains.
> Here's where I must return to Whitty's initial logic of deaths merely being brought forward. I don't think this can hold true anymore if we persist with the same strategy under these changed conditions, for a number of reasons. Firstly, the 1000 or so deaths a week we saw from July to now were ostensibly those we would otherwise have seen from October 21- March 2022.
It's worth keeping in mind that a disproportionate chunk of those are people who have declined vaccination, a bit under half of under 70 years olds to have died.
Harsh, but I'm going to set the unvaccinated aside when it comes to considering losses.
> Difficult to judge with the very incomplete deaths data we have over Xmas/NYE, but unless these decline dramatically very soon, we've just let ourselves be nudged into accepting a very high level of non-seasonal mortality, as the deaths we're seeing now have been brought forward from April and onwards, which cannot make sense given normal levels of mortality at that time of year.
The majority of vaccinated deaths - about 90% I think - are coming from people aged 70+; one Covid infection looks to be on the order of as lethal as a year or two of life at that point. If we move to endemic circulation, it's clearly - at present - a significant rising factor for mortality rates in the over 70s.
What isn't clear to me is if this is a sustained risk going forwards, or if the majority of vaccinated older people who survive their first breakthrough Covid infection go on to have a better chance with their next one - partly through selective losses and partly through broader immunogenicity.
This is where I see the meaning in Witty's comment - moving to endemic circulation everyone is going to have to roll the dice on their first breakthrough infection, and delaying that raises the risks through getting older without broader priming of T-cell immunity (likely more related to the exponential-with-age mortality risk of Covid), and it raises the risks through immune wanning from the vaccines, and it raises the risks through increasing genetic divergence of the virus and immunity (if we held out until son-of-omicron with as many mutations again emerges, T-cell immunity could be much more significantly at risk...?)
If elimination is off the cards, everyone has to roll the dice. Not once, but every 1 to 3 years or so. Lots of tangible and intangible risks to delaying that (I'd argue we're not really bringing deaths sooner, we're no longer deferring them as much as we were by the way)
Of course there are intangible benefits to continuing to defer exposure as well - therapeutics. Nothing is really certain until data is in on their real world use.
> Secondly, healthcare: rationing of emergency care, Cat 1 + 2s not being reached in effective times, NHS staffing decimated (in the literal sense, classical scholars) cannot fail to have a knock-on effect on both non-covid excess deaths and population morbidity: a lot of progress made over the last few decades against all sorts of urgent life-threatening conditions will go into reverse.
Totally agree. I'm still hoping Offwidth starts a thread on this. In terms of myself and my young family, I'm much more worried about what's happening to the NHS than about Covid now. That's what has warring for our future.
> Thirdly (and this is related to point 2 and, I think, the most hazardous likelihood), widespread infection increases, by a nontrivial factor, the number of people living with a new pre-existing condition who previously were healthy, and so they join the ranks of the vulnerable, with the difference that their potential deaths have been brought forward not just by a couple of months: in effect, their age-based risk has been accelerated.
But if we can't eliminate the virus, what's the alternative?
> Follow such a policy of temporal displacement of death in full consciousness of its implications and things start to go all Logan's Run rather quickly...
To put a different perspective of this; these are deaths displaced from April/May 2020 to late summer 2021; displaced through the use of lockdowns and control measures short of lockdowns and through vaccination. We're still displacing an awful lot of deaths through control measures and many older people being very careful.
> In that light, I could even make sense of some of the most apparently nonsensical parts of Gov's approach - doing nothing about ventilation, blathering anti-mask pseudoscience (Robert Halfon MP wins my 'Twunt of the Day' award today for his outstanding efforts), refusing to update the testing criteria, denying airborne transmission, insisting schools are safe and so on - as artificial accelerationism.
I can't make sense of some of these - whilst I think everyone has to roll the dice eventually if elimination is off the cards, we can stack the odds in people's favour. High viral load situations are a result of bad building designs that don't give people a healthy environment. Nobody should be getting particularly high viral load exposure and the barrier to addressing a lot of this has been embarrassingly low.
> Unfortunately, a variant that displays both vaccine escape and reinfection potential doesn't just take over that job of accelerating population level immunity. Rather it means the logic of raising spread now in order to reduce it later is broken, the infection control measures available to us are rendered insufficient, the vulnerable groups in society are placed in greater hazard, and healthcare capacity breaks down.
I still see it is an acceleration; I still see the goal as moving us on to an endemic circulation pattern as fast as safety possible to mitigate against significant breakage of antibody and T-cell epitopes from S-protien vaccines, and just because that's all we can do now - delaying the inevitable opens up a wider gap from all sources of immunity to the inevitable. This is why I was so agog at the Valneva decision because a well adjuvanted inactivated virus vaccine that they claim (no published data last I looked) to have a good T-cell response to multiple viral proteins is the obvious next step in taking the pain out of our transition from a pandemic to a truly endemic pattern.
I think I'm as stymied by you by the current response and by many events over the last 12 months, but coming at it from a different side.
> [btw, what sources are you using for Germany? What I see from the RKI - Xmas reporting lag aside - and hear from friends there is very different.]
The OWiD data explorer - https://ourworldindata.org/explorers/coronavirus-data-explorer
It'd worth looking at the 7-day moving average and at raw cases; there are day-of-week effects and a festive sampling low; the case rate has stopped falling and may or may not be rising; the "Omicron share" metric shows it landing significantly in the last week - against a trend of falling cases and coming from a share of 0% this means omicron cases must be rising unless their measurement is highly targeted. Give it another week... ???
Post edited at 21:18