delta, delta, delta (variant)

can i help ya, help ya, help ya? (yes, maybe it can)

delta variant has become the most recent cause célèbre among the purveyors of panic.

many are describing it as more contagious AND more deadly.

like so many other claims about “scarients” this is, frankly, bunk.

one might even go so far as to say that the delta variant, at least thus far, looks to be an extremely good sign and is cause for confidence, not concern.

it’s more contagious, but also has a 96.4% lower CFR than historical variants.

its CFR is in line with a very mild flu or a common cold.

contrary to widespread claims, it looks more like inoculation than devastation.

surprising no one, the NYT is leading the charge on “be afraid.” but should we be? this chart alone starts looking like it flat out refutes at least half their claims.

it’s also quite a misleading manner in which to present this. let’s see if we can do a bit better:

cases are WAY down from january, but are ticking up. BUT, deaths are going nowhere. the case rise dates back 3 weeks, so this is right about where we should expect to see deaths begin to rise as well. that will warrant watching. BUT, as many long-term readers will recall, case data without reference to testing levels can be EXTREMELY misleading. i think it’s misleading us here.

as a proxy for the testing level adjusted rate we can use the % positivity of test results. this will not give us absolute numbers, but it will give us better directionality and YoY comparability. as even a cursory look demonstrates, it does not support notions that delta variant is causing cases to run out of control. it actually, thus far, shows the opposite.

not only does it remain extremely low at 0.60%, but that positivity rate is WAY below the EU avg, US avg, (both above 2%) and, perhaps most telling, the same date last year in the UK which was 1.10%.

positivity is 45% lower in the UK than same date last year (using 7DMA from june 8th, most recent available in THIS dataset).

that is not consistent with some new supervariant making cases run out of control. it’s consistent with massive disease burnout and community immunity. it is, thus far, confirmed by the deaths figures.

the question then arises, “will it stay that way?” the odds-on bet would seem to be “yes, especially if the delta variant becomes dominant.”

that’s because it looks like the delta variant has a CFR more than 95% lower than other variants.

this is entirely in keeping with basic biological and epidemiological prediction and expectation. a virus is not some evil foe seeking to maximize harm, it’s a set of biological instructions trying to self-replicate. harming hosts is maladaptive. the evolutionary gradient of a virus as it becomes endemic is to be more contagious and less harmful. ideally, it would pose no harm or, as many bacteria have managed, to become outright beneficial.

  • a virus becoming more contagious in the late stages of a pandemic is the base case prediction.

  • a virus becoming less harmful in the late stages of a pandemic is also the base case assumption.

claims to the contrary are an extraordinary contradiction of historical data and biological imperative. such claims would seem to require extraordinary evidence and it is not present here. the evidence supports the base case:

the delta variant looks somewhat more contagious and dramatically less dangerous.

this data comes straight from the UK variants of concern reporting. (dated 11 june 2021).

look at the CFR figures. 0.1% vs 1.9% for alpha 1.4% for beta, 1.9% for zeta, and 2.8% overall historical CFR for cumulative covid in the UK. (calculated using the cumulative counts from our world in data dataset)

based on historical:

0.1%/2.8% = 0.036 = 1/28th as deadly

this is a 96.4% drop in CFR.

0.1% is more than 75% lower than most flu variants.

this is not a CFR over which you close a country, it’s one that provides no pretext whatsoever to impose any mitigation at all beyond “please stay home if you feel ill.”

we know this because we have a thing called “human history.” no one locks down a country for an extremely mild flu. no one. nowhere. not ever.

and based on the CFR data from the UK so far (based on deaths from oct 2020 to june 2021) the delta variant has a CFR akin to a very mild flu. i’ve seen no data to suggest otherwise (but am open to some if people have it) nor are we seeing hospitalization spikes etc.

it does seem to have a higher secondary attack rate than other variants, which, again, aligns with evolutionary and virologic expectation. more spread, less harm.

  • this is exactly what late stage endemic virus looks like.

  • it is, in fact, what you WANT it to look like.

it’s what makes a pandemic end. you cannot eradicate a virus. covid zero is a ridiculous and impossible task. but having the virus shift to a variant that spreads faster and poses so little risk is the next best thing.

you WANT delta to be all over the place. you want it to be the one that goes endemic. if, indeed, it winds up to be far lower risk than flu, then this is well and truly over.

thus far, this is where all the evidence points.

delta is a source of very low risk community immunity relative to past variants and massively shifts an cost/benefit analysis if it becomes dominant. (not that the UK seems to care about such things)

anyone using this variant as a pretext to delay opening does not appear to be “on the side of science”. it’s just not warranted. this is the expected late stage behavior of a pandemic ending and a virus going safely endemic.

it means this is just about over. delta spreads better and is 1/28th the CFR. having it become dominant renders covid about as dangerous as a common cold.

go live your life.