We may be reaching “herd immunity” pretty darn soon in some states.
I just threw this together. I haven't seen anything like it and I was, genuinely curious where each state stood. The numbers in the graph have lots of limitations (see below). But, even given all of these limitations, I still think this is pretty cool to see.
“Progress towards herd immunity” is a VERY rough estimate = Total cases x 3 (to account for under-reporting of asymptomatic cases) * 80% (to account for reinfection rate among naturally infected) + fully vaccinated x 90% (to account for efficacy of vaccines) / total state population (NOT eligible)
What number do we need to reach? Well, we aren't too sure, especially on a state-level. This will be dependent on variants, and population, and density, and travel, and many other factors. We should know when we reach our goal when transmission comes to a halt among the unvaccinated or unprotected (like kids and/or immunocompromised).
Enjoy!
Love, YLE
P.S. This gave me flashbacks to the early YLE posts, where I was scrambling for data (like every other epidemiologist) and spending nights throwing together Excel graphs because we didn't have pretty dashboards, just to figure out what was going on. I called them "data driven updates". I know some of you were around back then and might remember. We've come a long way.
And here it is stratified by protection type…
Limitations...
The overlap between vaccinated and previously infected (I don’t even have a guesstimate of what this is; let me know if you've seen literature on this)
It also doesn’t account for natural immunity (and specifically natural immunity from a mild infection) not protecting against some of the variants of concern, thus causing reinfections. But #1 and #2 might, honestly, cancel each other out
It also uses population sizes from 2019
Doesn't account that JJ has lower efficacy than Pfizer/Moderna
It also assumes that the underreporting rate is 3x. I’ve seen this as low as 2x and as high as 10x
It doesn't account for partially vaccinated
Thanks for this. I am a veterinary epidemiologist and have calculated quite a few herd immunity estimates in my day. What makes me throw up my hands for humans is the definition of the "herd". We assume a homogenous distribution of immunity and transmission likelihoods, and farms can often meet that assumption. Heterogeneity due to the plethora of socio-economic factors just drives up the estimate and I don't see how an estimate less than 90% can hold.
I am an old, very retired and only previously and many years ago, certified PA who has practiced no medicine in over two plus decades. I found your site today on my Next Door site and fell in love with it almost instantly, despite having no training in epidemiology at all (well ... I did clinically recognize that having multiple people at a ranger training camp, back in my own heyday , was weird ... right after I had reported to the commander at a staff meeting shortly after that we had to hospitalize that specific student at a local hospital but "it is winter and pneumonia when your students are tired, hungry, and trapped outside, is not that unusual" only to go back and have four more patients waiting for me with the same symptoms). That little venture got me asking the CDC for help and having my hospital commander insist I go down to the Florida ranger camp and follow up on all the guys we treated to try to break the spread with penicillin or erythromycin to prevent the strep. pneumonia that was causing the problem. We succeeded. and most students finished the grueling training.
Anyway, your site has charmed me and maybe I can get some of my military PA's to sign on too. I think I will go to their page and do that RIGHT now. Thank you ma;am.