[nudephil (OP)]

Here's a hypothetical from listener Giles...

In theory, if everyone in the world could self-isolate for 14 days and have no contact with any other person, would the coronavirus disappear completely? And if not, where would the reservoir of the virus remain?

Also would other diseases disappear?

Thoughts?

[Bored chemist]

Well, there are practical problems- all the very young children and many adults would die.

But as far as I can tell, yes, we would wipe out the virus .
It's possible that it exists in some other species- the best suggestion seems to be a bat.
But it's likely that it had existed in those bats (or whatever) for ages before it found us.

It's quite possible that we would manage to wipe ourselves out before "Covid 19" resurfaced.

Or it might be that some subset of sewer rats would act as a reservoir.
We simply don't know.
I would quite like to know how the  sales of immodium and other anti diarrhea drugs are doing, given all the hand washing that's now happening.

It's also entirely possible that some country somewhere will have a lower than average death toll over this period due to reduced road deaths, and reductions in otthe diseases like flu and the common cold.

[alancalverd]

Delete "any other person" and substitute "physical proximity only with persons of the same infective status". Then  the answer is pretty well "yes", as far as human infection is concerned. This is the whole purpose of quarantine, and it works very well wherever it is applied rigorously. You might end up with the death of the entire crew of a ship at anchor on the quarantine buoy, but whatever it was that killed them would not infect anyone else.

Fortunately it seems that those who recover from COVID are probably not infectious thereafter, so 100% quarantine would be short term, effective, and have little impact on "the economy". It worked for ebola. Present efforts by western governments are more like pissing into the wind. You can't negotiate with a virus.   

[Petrochemicals]

In that case how long for all viruses, must be worth the expense comared to all the medical treatments to counter such viruses, small pox has gone and repaid its vaccination programme millions of times over.

[gilesr1000@gmail.com]

Thanks for your observations..v interestingly... obviously impractical due to the high number of deaths of the vunerable...what of other diseases? G

[alancalverd]

Back in the days of the Cold War we planned and exercised a 7-day shutdown and curfew following the sudden nuclear destruction of all public utilities. All the indications were that most folk who hadn't been killed or seriously injured in the initial attack would survive and emerge smelly , hungry, but fit for duty.

Given at least a month to prepare the army to deliver rations and support the civilian emergency services, with no disruption of utilities, a 2-week lockdown would have been effective in preventing the spread of COVID and far less distressing and disruptive than the 2-year chaos we now face.

The only viral disease that has been eliminated is smallpox. It took around 1700 years from identification to elimination, and 10 years from the industrial production of vaccine to final elimination. In the meantime, quarantine worked wherever it was applied. Same with bubonic plague.

There are only two viable approaches to the control and elimination of human-vectored viral disease: quarantine and vaccination. Quarantine works within weeks if it is done thoroughly, and is within the scope of a competent government. We do not have a vaccine for COVID, and nothing a politician can do will make it happen any quicker.

The problem is that quarantine is electorally unpopular because if it works, you have nothing to show for it, whereas airy promises of supporting vaccine research and fatuous testing do at least produce a visible product, even if it is wholly ineffective. 

[evan_au]

if everyone in the world could self-isolate for 14 days

The problem is that people below the poverty line with no running water don't have the option to self-isolate for 14 days.

Communicating the period of the lockdown would not work in remote jungle/desert areas.

That means that there will still be pockets of human infection circulating somewhere in the world. It will re-emerge as soon as the 14-day lockdown ends.

[alancalverd]

It is also likely that those remote from "civilisation" have not had contact with the virus, or if they have, will almost certainly recover or die without passing it on to anyone else, so substantial re-emergence is unlikely.

History is full of "savages" being wiped out by the diseases of traders and missionaries, but very few vectors introduced zoonoses to "civilised" society until unquarantined air travel became the norm.   

[Bored chemist]

Communicating the period of the lockdown would not work in remote jungle/desert areas.

What's the difference between a group that's incommunicado because it is  quarantined, and a group that's incommunicado because it's remote?

[Petrochemicals]

It is also likely that those remote from "civilisation" have not had contact with the virus, or if they have, will almost certainly recover or die without passing it on to anyone else, so substantial re-emergence is unlikely.

History is full of "savages" being wiped out by the diseases of traders and missionaries, but very few vectors introduced zoonoses to "civilised" society until unquarantined air travel became the norm.   

Funnily enough yesterday I was reading of greenland, a norwegian dominion until the ravages of the black death brought norway to its knees. Fast forward 200 years and the Europeans export viruses they have immunity from to the New world and wipe them out. If the natives of the americas had the virus first maybe it would be them in the majority and a few european reservations left!

[evan_au]

What's the difference between a group that's incommunicado because it is  quarantined, and a group that's incommunicado because it's remote?

The length of the chains of infection.

If we assume that a person becomes infectious 4 days after exposure, and remains infectious for 5 days (to pick a rough average)...
- If everyone were isolated by themselves, the infection would burn itself out in 2 weeks. The chain of infection has length 1.
- However, if a family of 4 is isolated, one person could have it, 5 days later someone else catches it, 5 days later someone else catches it, and you come out the end of the 14 period with infectious individuals. The chain of infection has maximum length 4.
- Imagine some remote tribe with 50 individuals. That means the virus could be circulating in that community for a month, and the virus could re-emerge next time they have contact with someone on "the outside" - despite everyone else being in lockdown for 14 days.

I can't see how a 14 day global lockdown could work.

But 14 days quarantine is certainly effective in wealthy countries for passengers arriving from overseas individually or in families, put in quarantine for 2 weeks in a hotel, with regular testing.

[Bored chemist]

I can't see how a 14 day global lockdown could work.

It can't.
But it illustrates a point.
It explains to people how quarantine, and other approaches work. That might be valuable. We just need to explain it to the PM.

Imagine some remote tribe with 50 individuals. That means the virus could be circulating in that community for a month, and the virus could re-emerge next time they have contact with someone on "the outside" - despite everyone else being in lockdown for 14 days.

True, but it is unlikely that most people's desire- just as a global lockdown ended- would be to go looking for obscure groups.
It's not perfect, but it's likely that 14 days would still work.