[tdfx]

I've heard this many times but I don't understand the thinking behind it. How could a lockdown shorten the duration of a pandemic? AFAIK there's only three ways a pandemic ends:

(1) eradication: we control the spread so effectively through testing, tracing, and isolation that no more new people are infected

(2) herd immunity: enough people get infected that the potential pool of new hosts causes the transmission rate to decline

(3) inoculation: we find a vaccine with high effectiveness and somehow deliver that widely enough to create the herd immunity situation

It seems lockdown can only help with #1 and I'd say the horses have already left the barn on that one. The only things lockdowns can do at this point are to prevent number of acute cases from overwhelming the hospital system.

I'm not against lockdowns in extraordinary public health emergencies, but let's not pretend they are getting us any closer to a finish line.

[the_gastropod]

Option 1 is the ideal case, yes. And New Zealand pulled it off (unfortunately, it was undone when a covid patient re-entered the country). But it's not the only benefit. Reducing the number of cases obviously reduces the risk of the disease spreading.

The idea is to seriously lock down / wear masks, etc. for ~6 weeks to get to a point where the case-load is so small that it's manageable with little effort (not back to 100% normal). Instead, the U.S. strategy has been to put in medium effort / inconvenience indefinitely.

[SpicyLemonZest]

New Zealand officials don't currently believe that their new outbreak was caused by a patient re-entering the country - they haven't found any link between the detected cases and overseas returnees.

No country I'm aware of believes that even the smallest outbreaks can be handled with little effort. Health officials across the globe have been consistently saying that the coronavirus will spread unless people stay very far from normal.

[zaroth]

New Zealand is the perfect example. They have zero immunity, therefore they have to stay absolutely quarantined from the rest of the world indefinitely.

If a vaccine is only partially effective, and their tolerance for cases is literally lockdown at the first case, then they will never re-open.

[xapata]

> vaccine is only partially effective

Different vaccines will have different efficacy. None will be perfect.

[qubex]

A metaphor, if I may: think by analogy to the other famously exponential process, nuclear fission. When neutron flux gets too frisky, you have to throttle the reaction or face a catastrophe. You don’t need to disassemble the reactor to shut it down, it suffices to slam in the control rods and mop up those neutrons so they don’t trigger further fissions. Social Distancing is the “explosive dissassembly” of epidemiology: if the nuclei get too far apart (because the reactor has detonated) the reaction ceases because most neutrons “go wide” and don’t hit another nucleus. We’ve had to rely on the latter because as of yet we don’t have suitably effective control rods to scram the core. Lockdown is all about keeping the fuel elements sufficiently far apart so that the reaction goes sub-critical and eventually peters out (or reaches some background level).

(“Argument by analogy is very powerful and entirely fallacious”, so make of my words what you may.)

[tdfx]

Sure, I've actually used that analogy before myself, so I can't judge your use of it :)

My point was that in this case, people are expecting lockdown to stop the reaction entirely, when in fact the control rods are only intended to slow it down. The post I replied to seemed to believe that lockdown was intended to shorten the duration of the pandemic, when in fact it has the opposite effect (for the purpose of getting good side effects like keeping ICU beds available).

[xapata]

Right, but the lockdown helps us choose exit door 3 (inoculation) instead of 2 (herd immunity).

[partyboat1586]

Providing we can stay locked down until the vaccine is ready.