Isn't there evidence that a high enough proportion of those low risk people would require hospitalization too and that would overwhelm the capacity? That's my only remaining concern about the idea.
FWIW I don't think herd immunity will work given that other corronaviruses (the common cold) mutate frequently, it is too early to tell, but TBH a risky move for any government which can see positive results from other approaches elsewhere.
The current approach is really bourne out of a failure to act early - that $1 antibody testing kit was overlooked by ministers until it was pointed out to them by a journalist. That airports weren't locked down immediately with a 2 week mandatory quarantine, drafting ex-NHS staff only last week was 3 weeks late etc
A cynic might point out that this virus is likely to kick the can down the road wrt pensions /ageing populations /finding an economic model not based around GDP/having more kids. There is a rumour that a senior MP made comments about collateral damage, if you were really cynical it might be pointed out that this constitutes a large portion of some parties' voter base.
There are some silver linings- after all of this teachers are likely to be appreciated as is a national health service (Medicare anyone?), remote working will be easier, and there are some amazing stories of compassion out there!
- Isn't there a significant risk that immunity after infection might wear of too soon after infection for herd immunity to be practicable, at least without driving up the deaths yet further?
- Isn't there a significant risk that we end up with a lot of people who survive but have long term health problems?
- Wouldn't the fact that no one else seems to think herd immunity is such a hot idea any more mean the UK faces a high risk to be completely quarantined off by other countries? Brexit probably doesn't reduce the chances of that happening either. Could that not have a few bad economic and other effects?
- Isn't there a significant risk that isolating vulnerable people or the infected in ICUs may not work as well as intended? What if a lot of nurses and doctors get infected and pass it on to other people who have no chronic problems but are temporarily weakened? What if it turns out that seeing a lot of people die miserably without being able to do much about it for weeks on end takes its toll on the current crop of health care professionals or the UK's ability to recruit future generations?
- Wouldn't that most likely mean giving up on eradicating Covid-19 completely? Is it really desirable to permanently reduce life expectancy by keeping it around forever?
- What if the virus changes in an unanticipated direction? Would the herd immunisation strategy not put exactly the type of evolutionary pressure on the virus that you don't want? Namely to become more virulent? Is that not a bit risky?
That ship has long since sailed.
For what it's worth, I think eradicating something world-wide that has already spread widely beyond the relatively competent and affluent countries is going to be tough. But personally, I'd much rather see it eradicated in just competent and affluent countries than not at all.
With something this infectious all it takes is one visitor from one of the have-not countries to put the have-country into total lockdown. That's not a realistic plan moving forward either.
1. People don't just start to magically teleport around if you restrict their travel. I know that defies common wisdom, which is presumably why the UK and others kept (keep?) importing people from disease Epicentres like Milan or Teheran en-masse right up the point of total lockdown. But if, for example, Japan, the UK or Australia decide they don't want Iranians to visit their shores for a while, at least not without on the spot testing, automatic two week quarantine or other heavy restrictions: what is the would be Iranian mass-infector going to do about it? And is greatly restricting travel from incompetent countries really going to wreck your nation?
2. Vaccines are cheap. If it's possible to create a vaccine that is sufficiently safe and covers enough strains of the virus, you can just vaccinate enough of your population that the disease will, effectively, no longer be very infectious. Then you can intelligently spend some comparatively trifling sums to make such vaccination programs available to countries that genuinely can't afford them.
If herd immunity would have worked, then a vaccine will work. That might be 2022, but it's definitely not forever.
I won't even claim that severe lockdowns (which is not what anyone in the US or UK is facing) is the best solution.
However, in the absence of almost any reliable knowledge, it's probably the ONLY rational plan based on the fact that the one thing we do know is the method of spreading, and locking down will prevent that spread.
Everything else is still up in the air. We have to buy time, time to find effective antivirals (work in progress), time to get an effective vaccine (work in progress), time to understand the virus enough to know even such a simple thing as how long somebody who's had it and recovered might be immune for. That one critical number you have to know in order to know if a plan like the herd immunity idea is even remotely feasible, that one critical number that NOBODY KNOWS.
Isolation is, from everything I've read, the only strategy currently supported by the available evidence. Maybe in six months we'll have data that says herd immunity would have worked, but we really don't know right now.