When does it end?

The Quarantine Zone
1

It’s fairly easy to predict that within thirty days or so, the graphs will start flattening out; even with more widespread testing, due to spreading immunity of those who have already survived and recovered, and social isolation measures.

What seems a lot harder to predict is what happens after that. Until there is a vaccine, which seems at least a year away, what could possibly happen to get any kind of a handle on the virus? It seems to me that as long as there is no way to prevent transmission without totally disrupting daily life, we are going to be in this holding pattern.

Antibody tests would help a lot in returning those likely-immune people to work. But other than that? Any ideas?

2

Probably a gradual loosening of restrictions to turn the curve into a plateau that stays below the capacity to treat cases. After most people get it, then the plateau will decrease. Some places, like nursing homes, will remain under tighter restrictions than the rest of society. Sanitary habits might become permanently changed.

3

This is correct, and people need to get used to it. Short of a miracle, no vaccine will be widely available for 18 months or so. During that time, we can either protect people by isolating ourselves, or we can put it in Darwin’s hands until enough of the herd has self-immunized by surviving the illness (leading to tens of millions of people dying).

There’s really no middle ground unless we try to delineate “clean zones” where people can only enter and move freely if they test negative for the virus, which would be of dubious benefit. Plus we still lack the resources to test enough people right now.

Aside from that, I have an almost 100% expectation that this is moot because there will almost certainly be a rebound stage to the pandemic. Bored, frustrated, economically devastated citizens will clamor to end the quarantine before it’s safe, and we’ll see a devastating rebound that will begin to peak with the regular flu season.

4

Well, measles & mumps became diseases of childhood, because pretty much everyone caught them, then were immune for life.

If Covid-19 remains with us, people who have had it and retain immunity, may have a lifetime immunity by virtue of the fact that IF it turns out immunity wanes, as their immunity wanes, but while they still have it, they are exposed, and fight it off, while having mild or no symptoms, and then it’s like getting a booster shot-- two-three more years of full immunity. This is a guess, just based of what a cousin with a PhD in microbiology explained to me regarding the reason people used to retain lifetime immunity to pertussis, but now adults need a vaccine every ten years.

And, while measles is dangerous at any age, and mumps is nothing to sniff at, mumps, at least, is much easier in children than it is on adults.

Covid-19 appears to be easier on children than adults.

We eventually may have a society where nearly everyone gets Covid-19 in childhood, is not very seriously affected, and then retains immunity for life.

That does not mean that there will not be children severely affected. It may be very serious in asthmatic children, and a killer of children with things like cystic fibrosis, or the hereditary form of emphysema. It also may miss some children, resulting in adults getting it occasionally, and becoming seriously ill.

And we don’t know what will happen in 30 years to young, recovered people. Chicken pox leads to shingles. Who knows what Covid-19 could lead to?

So, we will not stop seeking a vaccine. We will not stop seeking a treatment.

We found a vaccine for Ebola in a relatively short time, from the time research actually began in earnest. We also found extremely effective treatments for HIV. We turned HIV into a livable condition, like Type 1 diabetes. The next step in HIV treatment may be long-term delivery devices, like the types used for some birth control, or some of the pills used for osteoporosis. There may even be drugs that allow allow unprotected sex-- not that I’m advocating lots of that, but it would make it possible for HIV+ people to have children the old-fashioned way.

I’m just saying that the Jenner vaccine was the model for vaccines for a long time, but in the 21st century, unimagined treatments are happening.

Eventually we will be able to effectively treat, cure, or vaccinate for Covid-19.

And somebody will probably claim it causes autism.

5

These things only work when people don’t think they are being hoaxed. They only work when you don’t have morons inviting large crowds to get together. The Spanish flu was still killing people more than a year after it was first noted - lets hope that is not the case here.

6

There are a few strains of this virus. Also, there are people who have been re-infected after recovery.

7

The “best case scenario” is basically what you describe. Quarantine is like a heavy weight pushing down on the virus from above and preventing it from spreading, but as soon as it is lifted, the disease will spread like wildfire again. So we can use control measures like we have been doing to slow the virus, and at the same time ramp up testing and isolate any positive cases to pick away at the virus’ remaining strongholds.

But what seems more likely is that as soon as the curve plateaus our politicians will reopen everything way too quickly and we will have a rebound outbreak as large as the original.

8

Let’s go to the quarry and throw stuff down there!

It’s fairly easy to make flippant and baseless predictions, aye.

9

I don’t think it’s baseless. The whole idea of social distancing/hand washing is to “flatten the curve”, why do you suppose that won’t work?

Just because the curve is flatter doesn’t mean it will fall off. It’s just flatter.

10

Things are changing rapidly, but the last I saw there were two known strains of the virus, “L” and “S.” There may be some differences in response to the two strains, but not much is known. Or wasn’t. Do you have info that says there are more than these two?

As for reinfection, it wasn’t yet known if that was possible. There were a few reports of it out of China and Japan, but there was also a possibility bad testing was to blame and not reinfection. Have there been any confirmed cases of reinfection?

11

The specific answer is that it ends when R0 is <1. Can’t have a epidemic with a basic reproduction number below one.
This in turn means that this epidemic ends when infectious persons pass the disease to less than one susceptible person on average.
This will be achieved when infected people only meet non-susceptible people. Either because those they meet are immune through having had it, being vaccinated, or sufficiently shielded from transmission.
Once vaccines are widely available, assuming a low mutation rate, it’s over.
Before that point, when testing for the virus is finally widely available, we can isolate those who have the disease, and so keep R0<1
And when antibody testing finally becomes available, we can have those with antibodies be the front-line in dealing with the infected, supplemented by susceptible personnel with appropriate ppe (gear)
So: it’s over when we have large numbers of tests for virus, aided by tests for antibodies and availability of ppe. I hate to sound like a dearly departed board-member, but those are solvable problems, not defined by the time requirements of vaccines.

12

Some researchers think COVID-19 immunity will be like that of other coronaviruses:

13

I’ve seen this claim of reinfection repeatedly around here and of course other places on the interwebs, always without a shred of evidence to back it up. There are apparently several minor variations which allow tracing the origins of different infections; based on serotyping Iceland has determined separate contagion paths from Northern Europe, Southern Europe, Asia, and North America, but there is no indication that exposure to one variant doesn’t imbue significant if not complete immunity to the others. On the other hand, there is recent experimental evidence that reinfection could not occur in SARS-CoV-2 infected rhesus macaques. It is certainly possible that a mutation could create a new major strain that would not prompt an immediate immune response into someone exposed to an existing strain akin to how the Influenza A and B strains that are endemic in human populations occasionally become highly contagious and virulent, and this may even be likely as virologists think that the SARC-CoV-2 virus is likely to become endemic if an effective vaccine is not developed, but even if that is true we probably won’t see another outbreak of this magnitude just because endemic strains tend to be less virulent over time.

This is true. Short of a universally applied vaccine, new infections will taper off but won’t go to zero in the foreseeable future. However, if we can both push that off until the medical system isn’t as overwhelmed as it is now, and develop effective anti-viral treatments as well as widely deployed early detection so those treatments can be applied early enough to be effective, we can likely save the most at-risk people. Hopefully this also encourages people to adopt healthier lifestyles, e.g. quitting smoking, getting exercise and nutrition to boost immune response, following better public hygiene practices, et cetera. If we’d just stop shaking hands and clean door handles more often that alone would make a significant impact on many communicable diseases.

Stranger

14

One thing to also remember is viruses become less virulent as more people get exposed. Those people that have more severe forms stay home and get better (or die). Those people who have milder cases go about their business and pass it and the non-infected get it and also get a milder case.

This was one of the issues with the Spanish flu. The soldiers on the front lines with mild forms were told to stay there and keep fighting. The ones that were really sick were taken off the front lines, by train and cars though the cities an in the process exposed civilians to the more deadly type.

Just the opposite of what is usually seen.

You will also see ironic things, like right now NY City has over 75,000 cases, in two or three weeks, most of those people will be better and immune, now they can go back to work. So NY City will likely be ready to open for business long before other areas of the USA.

So despite the fact it’s now suffering the most, NYC will likely recover economically much faster.

Yes, I realize I am leaving out the humanity and the tragedy of the situation. As Gracie Allen once said, while she was running for president, “A chicken in every pot sounds like a great idea, unless you happen to be a chicken.”

15

In a meeting I had on Monday, an expert answered this question by saying (to paraphrase): It will be over when between 60-80% of the population has gotten and recovered from the disease or when a working vaccine goes into general distribution and a similar or great percentage of the population has been given the vaccine. And a vaccine is still 12 months out.

16

I’ve seen that a lot. But a year or two of immunity is what we need. The reports I saw were people that were “reinfected” after weeks, not months or years. If people have immunity for a year, this round will end. It is tiresome to keep having to remind people that “gain immunity” doesn’t have to mean lifelong immunity to get this to die out.

The virus is going to mutate, which is why we get the common cold every year. But generally these mutate into more benign forms. By the time this comes around again, it is likely to be far less deadly if it has mutated to the point that our immunity this time around won’t protect us.

17

The numbers I’ve seen are similar, which is why I’ve been advocating for a long time that we control the infection rate instead of waiting for it to control us. I’ve been told I’m delusional for proposing such a thing. People take my proposal to mean we remove all the safeguards, let everyone go back to life as normal, and let the chips fall where they may. That is completely not what I’ve proposed. Instead, now, we have a random sample of people spreading the virus in uncontrolled ways. We will continue to get hot spots until we’ve made our way through all the major population centers and then slowly drift through the more rural areas. There are numerous issues with trying to do a controlled infection, but from my perspective that sure beats what we are doing now, which is simply waiting around for this virus to go where it wants. It will not die out with social distancing, unless we get really lucky, such as the warmer months making it less infectious or we find miracle treatments.

18

If you are at the stage where you can do a “controlled infection”, you are also at the point where you can quarantine only those who are infected, in fact, that might be easier, and would result in fewer deaths. If you cannot, actually, quarantine only those who are infected, you cannot do a “controlled infection”
The reason we are not concerned with Ebola right now is because during the outbreaks until now, infectious people were quarantined. (There now is a vaccine, but that is a recent development). That’s why Ebola is not of particular concern in Pittsburgh: even though we’re all susceptible, we are unlikely to encounter a carrier. The scale is orders of magnitude larger for Covid-19, but not impossible. It will require many, many tests be available.

19

Assuming that recovery leads to immunity and immunity transfer successfully transmits via plasma, that’s available to use already and it looks like they’re already going ahead with trying it in New York. It seems likely to succeed at stopping people from getting the illness, even if it will be less effective at curing them, once they’re very sick.

The downside of it is that, from a logistical standpoint, we probably won’t be able to do much more than immunize the elderly. But, on the pro, that’s like 80% of the people who require hospitalization.

Ideally, the President would be running an organized effort to get a list of elderly care centers, etc. and start prioritizing plasma shipments. Hopefully, a few counties and states will, as it stands.

20

The problem with quarantining those who are infected and trying to keep them from spreading it to anyone else is that if even one person isn’t quarantined they can spread it to many others. R0 is at 2.2 or 2.5 or whatever and the thing takes off like a wildfire.

What would happen if we exposed the least vulnerable to this now, all across the country. Places like Denver, Portland, Sacramento, etc. are not in crisis mode as we stand. The least vulnerable get it and some percentage need urgent care. We have resources to deal with that percentage now. And, in a few weeks, we have now reduced the number of vectors available by a huge amount. So now when the virus “naturally” gets into that area, there aren’t nearly as many vectors and the spread is a lot slower. Much slower. And, again, the number of critical cases is reduced, thus keeping the medical system from getting overwhelmed. Not only because we have slowed the transmission rate, but because we pre-treated some of those that would need treatment.

We must get to 50% to 80% of the country exposed. Period. We can do that by waiting for this to flare up in spots that hit everyone in that area at nearly the same time, or we can start to control it now and expose more people earlier and spread out that exposure.