Tuesday, April 21, 2020

Lock Downs, Herd Immunity, and Deaths

In the long run, the only way to control a highly contagious disease like Covid-19 is by establishing herd immunity, either via a vaccine or by letting the disease run through the population until some percentage are resistant. This percentage varies according to the disease, but for some diseases even 30% has a huge impact on the spread, especially if those are the most socially active people.

I am starting to see a lot of grumbling from people who say that with this disease, lockdowns will only increase the long-term death rate because they delay herd immunity.

The argument goes like this:

  1. Covid-19 is far more dangerous to the old and sick than to the young and healthy; yes it does kill some young, healthy people, but not very many
  2. Short of a vaccine the best way to control the disease would be to expose millions of comparatively young, healthy people to it until half or so of the population is resistant, which would probably be enough to greatly slow its spread
  3. Lockdowns keep this from happening, because most of the people they keep home are comparatively young and healthy
  4. The effect is to lower the rate of infection but extend its lifetime; this flattening of the curve raises the overall death rate by keeping the disease at a pandemic level longer, so that more older, sicker people end up being exposed

I have no idea if this is true. The sad toll of the disease in nursing homes shows one problem, which is that many of the old and sick are being cared for by younger, healthier people, and surely raising the infection rate among nursing home workers would end up killing lots of patients. I have a feeling that some of the people pushing to end lockdowns don't regard that as a bad thing, which bothers me.

Another point is that experiments with antiviral drugs are going on around the world, and remdesivir has already shown some promise, so delaying the disease might allow better therapies to be developed. That would also make the issue of hospital space more important, since we would have useful interventions to employ.

Anyway we have an experiment along these lines going in Sweden, where they have encouraged the vulnerable to self-isolate while letting the rest continue working. So we may end up finding out which approach saves more lives in the end.

As we re-open society it seems inevitable to me that vulnerable people will have to take extra measures to protect themselves. I see a lot in the news about the need for more testing and so on but I wonder if what we really need to put in place are measures to deliver vital supplies to elderly and immuno-compromised people, so they can stay safe while the disease spreads among healthier people going back to work.


JustPeachy said...

It's not that people dying in nursing homes is "not a bad thing". It's that it's probably inevitable. Do we get it over with now and get everyone else back to work/school/life, or do we drag this out for... how long? Six months? Eighteen? Two years?

What will be the cost of keeping vulnerable populations alive for an additional few months? It is the same calculation you have to make with, say, cancer treatment: How much is a chance at one more year worth, in dollars? A hundred thousand? A hundred million? Right now, the cost of preserving the lives of people who would very likely die of something else in the next five years anyway (look at the comorbidities) is absolutely astronomical.

I'm not trying to be callous. My parents are in their seventies and my mother has the whole poorly-controlled T2D package. This virus could easily kill her. I don't want that to happen, and we are being careful about quarantine. But realistically, she's not going to live to 80 on insulin. Is it really OK to sacrifice millions of people's jobs, businesses, schooling, church, and personal freedom, to keep my mom alive for a little bit longer?

I don't think it is. I think we should do what we can to protect vulnerable populations. We should be testing health care workers like crazy. Widespread antibody testing can't get here fast enough. We need to be doing frantic research to know as much as possible about the disease.

But ultimately, it's a virus. We get new ones all the time. How many have we successfully eradicated? Smallpox? How many years did that take? Did we shut down the whole world to do it?

szopeno said...

Then there is also an argument about viral load and the relation with a seriousness of a disease, that it's better to get lower viral dose (when you are outside) than higher (when you are locked in home with someone sick). Frankly I am not qualified even to try to estimate whether this is "not even wrong" area or merely "controversial".

Mário R. Gonçalves said...

I only know for sure that they are not telling us the whole plain truth. They chose panic instead of clear honest information. Political, health and media institutions formed a block of misinformation and manipulation, now they say no masks, then masks mandatory for all; now they say close business, them they say great loss of GDP.

It all seems a very bad theatre play, we are the fools.

Shadow said...

I don't think anything nefarious is going on. The way this lockdown was implemented reeks of last minute thinking. It's like no one ever planned for this; that no one thought through the alternative responses to a contagion like this. But that can't be. There has to be a plan. Perhaps it's buried in the basement of the NIH alongside the Arc of the Covenant, and everyone has forgotten about it, or they are too afraid of the arc to get near it. But there must be a plan. Right? Please! Where is Harrison Ford when you need him?

Seriously, I think the stakes are very high whether you do or you don't, and with powerful interests pulling and pushing from both sides, political leaders froze hoping it would go away. SARS did, right? For some reason in situations like this we embrace inertia. Who wants to be the first if you are wrong and your state's economy goes south for the summer? And why should we think all 50 governors are up to the task? Why should we be surprised that this president isn't? How many elected leaders have the guts to lockdown before transmissions and deaths make it obvious we should have locked down weeks ago? Who is that person? And would anyone have obeyed or would they have gone to the beach?

G. Verloren said...


Precisly. This was just Hanlon's Razor in action: never attribute to malice that which is adequately explained by stupidity.

We actually had pandemic plans in place, established by George W. Bush of all people, and they remained in place until President Spray-Tan decided to tear them up and throw them in a fire for no reason other than to fuel his own ego, Qin Shi Huang style.

Still, even without that, it's really a systemic problem of our leaders not being far-seeing individuals motivated by the good of the entire nation, but rather being short-sighted political game players motivated by self advancement. There are exceptions, of course, but they grow rarer and rarer. The corruption runs deep.

Susi said...

To add to our unpreparedness, the scientific knowledge about this virus is being updated daily. Not by the best practices (studies), but by those in the ICUs trying to save lives. They are using trier precious sleep time after 12 hour days to write and disseminate their observations to their world-wide colleagues. Thanks to their observations we are seeing that this is a whole body disease, rather than a respiratory disease.
I’ve put some of these observations on VirginiaCountryLife.Blogspot.com (No pride of authorship)