I think "herd immunity" is a euphemism for: This virus will see community spread of around 30% to 70% and it is long impossible to contain. The U.S. is preparing for 30%, The Netherlands for 50%, and Germany for 70%.
Herd immunity will be hard, since antibodies for coronaviruses last only about 4 months.
Even the strictest quarantines possible in the West don't compare to the mild quarantines in the East. The laws don't allow for contact tracing with GPS coordinates and credit card purchases, like they do in Singapore.
Quarantine methods put selective pressure on the strain types that are more infective and severe, since such mutations and recombinations are the only ones able to escape quarantines.
So the plan seems to be to turn this into a community virus, much like herpes or HIV. Then the selective pressure is for the mortality rate to drop and the disease becomes manageable. It would seem silly to damage your economy with heavy quarantine methods when local community cluster spread continues to pop up.
Of course, the UK government can not come out and straight up say this, but they seem one of the few governments that is realistic about facing this virus and its impossible to contain infection rate. I am guessing they ran the numbers from the Italy quarantines and based their decision on that.
> Quarantine methods put selective pressure on the strain types that are more infective and severe, since such mutations and recombinations are the only ones able to escape quarantines.
Mind sourcing this? This seems the exact opposite of what I'd expect. I'd expect quarantines to s left for milder strains that are harder to detect.
> Human intervention may have placed more severe selective pressure on the L type, which might be more aggressive and spread more quickly.
Harder to detect I would see in a strain that has a longer asymptomatic spread period. The only way for a virus to escape a strong quarantine and survive is to survive on surfaces longer, be asymptomatic longer, cause more severe illness (spread through cough and sneezes, especially in hospitals), linger in the air longer, etc.
on the contrary, more sever illness makes it less likely to spread, no?
You are always spreading germs around, if you have high fever or start coughing blood you'll get isolated but if you just have a runny nose you will keep living normally and the virus will happily keep infecting other people when you shake hands.
During quarantines people are not shaking hands. I am not saying quarantines necessarily select for a higher death rate (a dead host can not spread), but for a more severe disease (the main drivers of a spread are when people ultimately develop severe symptoms).
Community viruses mutate to see a lower mortality, severity, and infectiousness, since there is no selective pressure to have an r0 much higher than 1. For a community virus there is also no selective pressure to mutate to a vastly different strain, so the antibodies for other strains don't help, whereas if the virus is confined inside a city like Wuhan, the only way to reinfect is to mutate to a vastly different strain.
I think you agree with the parent comment. “put selective pressure on the strain types that are more infective and severe” does select for milder strains (the pressure is on severe strains to change).
> People regularly become ill with a cold due to a coronavirus and may catch the same one about 4 months later.
> This is because coronavirus antibodies do not last for a long time. Also, the antibodies for one strain of coronavirus may be ineffective against another one.
> The general trend of IgM peaking at ≈1 month after symptom onset and IgG peaking at 2–4 months was consistent among different studies.
The common cold is a coronavirus that people catch annually. As I understand it, it is because the cold evolves or the immunity doesn't last for some reason. https://www.who.int/health-topics/coronavirus
Some infections that people identify as common colds are coronaviruses. There's dozens of other viruses that cause colds, with most infections being a different family of viruses (rhinovirus [https://en.wikipedia.org/wiki/Common_cold]).
It's probably not a good idea to make concrete assumptions about a specific virus from the family it belongs to. A good place to look when starting to characterize, not necessarily a complete guide to how the virus will interact with our immune systems.
The coronaviruses that cause colds (such as CoV-OC43) don't mutate much. Immunity to them doesn't last long for reasons that aren't well understood.
Some other viruses that cause colds escape immunity through mutation, other non-CoV cold causing viruses escape are like CoV and also just have short immunity periods without mutation.
Over 200 different viruses cause common cold symptoms. Only about 15% are coronaviruses. It's usually considered unrealistic to vaccinate for so many different viruses, although there's been some research into vaccinating against a large proportion of them. The Guardian published a good article in 2017:
> estimated projections of as many as 96 million cases in the US, 4.8 million hospitalizations, and 480,000 deaths associated with the novel coronavirus.
All Western countries moved to fase 2 of epidemic control: Stop testing and contact tracing, since you have many many clusters of local community spread and no idea where it is coming from. They are hesitant to come out and outright say it. Some do, but not with permission of their superiors:
Mild cases continue to spread, and don't self-isolate, because they may not even realize they are infected.
China and South Korea have laws that allow for containment: If you message your friend on WeChat and say you have a cough, then you can expect a visit from the Chinese containment crew. If you buy cough syrup in the drug store with your credit card, then South Korea health officials know this.
Containment is pragmatically impossible with an r0 > 2 in the West. Just slowing down is possible.
In Italy they use old laws for murder when you violate your isolation and infect others.
Australia, NZ, U.S., Italy, they all see sustained local community spread. Australia is still exponentially increasing. Shutting down flights when there is local community spread is show politics, something to point to afterwards and say: We took decisive action. It is purely symbolic.
Sure, U.S. could pass emergency law and use their military surveillance systems to track, tag, and contact trace all of their civilians, as if they were Chinese spies.
But is this desirable in a free society? And what difference does it make when there are 100.000 infections in a single state, of which you will miss a 100 and start all over again 2-3 weeks later, but now with 99.900 angry citizens with guns?
One of the reasons that SARS-CoV is deemed a useable bioweapon is exactly because isolation security methods are very expensive and invasive at scale. The cultural damage would be enormous if people receive letters from the government after they had a private chat on Facebook about symptoms.
Initial response to isolated infections requires a different response to that you give an entrenched pandemic. When it always comes back from multiple countries and is initially undetectable complete shutdown trace and contain simply won’t work.
It’s a sensible measure to delay the spread, I don’t believe it will be effective in stopping the spread and it will be very damaging to the economy so not sustainable IMO.
Herd immunity will be hard, since antibodies for coronaviruses last only about 4 months.
Even the strictest quarantines possible in the West don't compare to the mild quarantines in the East. The laws don't allow for contact tracing with GPS coordinates and credit card purchases, like they do in Singapore.
Quarantine methods put selective pressure on the strain types that are more infective and severe, since such mutations and recombinations are the only ones able to escape quarantines.
So the plan seems to be to turn this into a community virus, much like herpes or HIV. Then the selective pressure is for the mortality rate to drop and the disease becomes manageable. It would seem silly to damage your economy with heavy quarantine methods when local community cluster spread continues to pop up.
Of course, the UK government can not come out and straight up say this, but they seem one of the few governments that is realistic about facing this virus and its impossible to contain infection rate. I am guessing they ran the numbers from the Italy quarantines and based their decision on that.