How more testing helps -- for dummies

[lljkk]

I can't follow the logic of how testing (for active infection or antibodies) is so helpful for lifting lockdown, unless the testing is massive, like 5 million/day to start with and on ongoing-basis for a long while afterwards.

Is someone a great communicator and can explain the strategy well.
Is 5 million/day the basis of the how testing would be helpful?

I don't think it's helpful for lifting lockdown exactly, rather that if we can get the numbers low enough through this lockdown that we could test every suspected case, trace contacts, isolate and quarantine to prevent the need for further lockdowns.

Whether or not we have the infrastructure or technology for this approach remains to be seen.

What @dippyavocado said. The key to any controlling any outbreak is identification, treatment and tracing. It’s like chicken pox but on a much larger scale.

Given the incubation period testing will be key to identifying and controlling numbers. It doesn’t work in isolation but it means that resources are appropriately targeted. For instance I see the 14 day household isolation period for certain symptoms becoming a statutory/routine requirement and requiring completion or testing before being lifted. Initially that will require a lot of testing and the infrastructure to administer it. Once our numbers are low enough this becomes a much more achievable goal.

cv19 is not like chickenpox. 85%+ of the population already has immunity to chicken pox and cp is rarely deadly. There's a vaccination for shingles and one for CP.

If we had massive testing, at same time would the schools and pubs all still be closed & non-essential travel still banned and people still asked to keep 2m apart & most work places closed? What would massive testing make different, and how?

Massive testing along with contact tracing is probably the easiest way to keep virus transmission controlled once you have got it broadly under control

My assumption here is that you want to keep infections at a seriously low close to zero level until a vaccine is available whilst at the same time giving people their lives back. This approach to my best understanding minimises both death rates and economic damage

It would mean that you could release people from lock down and hopefully spot any potential second wave whilst it was more of a ripple and isolate ; quarentine only people who had tested positive or come into contact with those people

It would mean that you would not have to isolate for 2 weeks every cough and sniffle, you would only isolate until you git test results back

It would avoid having to lockdown the whole country

by catching the asymptomatic people and then they can stop spreading it and isolate

By confirming it to symptomatic people so they can stop trying to push through perhaps mild symptoms and isolate

By combining it with contact tracing so anyone in close contact can isolate and stop potentially spreading it

Look how Germany or Korea are doing? by testing they have a clearer picture of how the infection is spreading, not just those going to hospital.
Plus by early intervention/isolation, you prevent infectious people spreading the virus.

Unless, somehow we get our testing up to speed, we will be in lockdown for months as we will never be quite sure how numbers are heading.

Antibody testing (if there is ever an accurate test?) allows those with immunity to go back to work once sufficient numbers have immunity.

But yes we will surely have to have social distancing until there is a vaccine or enough people have become infected.... so no Hols in the sun for year or two.

If people develop immunity, than identifying who has had it would be priceless for reopening. Those that developed immunity cannot get or give Cv-19 so they can go about life without problems. They could run shops, teach kids, etc.

However, I woudn't hold my breath for it to be sorted for a while. The antibody test has to be quite specific to be useful.

Also, if we know who has it and can isolate them, that would make safer for other people to move about. Some people will fall off the detection net, but that will keep numbers down.

The lockdown is to avoid the whole country getting sick at the same time. That is why it was so important to lock down as soon as possible. The less contact, the less transmission. That is all we can do now, while we are flying blind.

I'm not trying to be obtuse, honest.
I know no one knows what govt will do, I'm just trying to figure out what options the tests realistically create.

if you have a vision how that would work, then say so.

My best vision is like this:

Educational facilities stay closed. All symptomatic & their HH contacts on house arrest unless they can prove they are cv19 free. All mass gatherings banned and travel still restricted. But you can go to work if symptom free. Maybe masks required in crowded places and required contact tracing app on all smart phones. 2m spacing expected and enforced by any shops or venues that can enforce it. Tests only complement this picture because they allow release from symptomatic quarantined households if you test clear, usually within 72 hours.

Anyone who has had enough* (I think Singapore rule was 15 minutes close contact) contact with a confirmed case is also on house arrest for 14 days, regardless of their symptom level.

Have I just described South Korea to great extent?

If I have a shop, me & my staff all have immunity (in the lucky 4%).
I have immunity but 96% of my customer base don't have immunity.
Will I get enough customers to bother opening the doors?
96% of my customers can still infect each other...

Ditto schools & most workplaces.
I can see how immunity certificates would be priceless for the staff in places that must stay open, like hospitals & care homes.

I agree with points made by PP but I would also add that large scale random sampling would help identify the rate of infection in the population as a whole rather than just testing HCP's and people unwell enough to need hospital treatment. We cannot accurately calculate mortality rate until we have this information. If the mortality rate is very low it would raise questions about whether the economic damage is worth it. Numbers of deaths would still be tragically high because this is a novel virus but at some point we have to consider whether the economic fall out will result in greater loss of life.

@lljkk - I was making the comparison with isolation and chicken pox i.e staying away from people till spots are scabbed to illustrate that the concept isn’t completely alien. Of course covid-19 is nothing like chicken pox as an illness itself.

Contact tracing and testing also captures those who are asymptomatic or only get very mild symptoms.

You have to remember that we’re not attempting to eradicate covid-19 but to control its spread so everyone has the best chance at treatment and services aren’t overwhelmed. We haven’t seen much in the media about how they’re managing corpses at the moment but there’s a real risk that those services become overwhelmed which is a disease risk in itself. Ultimately we’ve got to live with this virus but the initial outbreak can hopefully be controlled to stay within the limitations of our infrastructure. To do that there needs to be information available about where it’s concentrated.

The random tests by the Dutch make me suspect that the lower levels of society infection and therefore the higher death rate estimates of at least 1% ( rises rapidly once a health system gets overwhelmed ) are probably accurate

Your best case vision is way too pessimistic

If virus levels were say 1 infection a year would you still close schools? Or 10 in a population of 67,000,000?

Provided we can get the infection under control then the test and contact strategy let's you keep infection rates in the 10s or even 100's of people at any one time.

At that point the costs of lockdown in terms of domestic violence killings would be far more than the deaths from the virus

And the risk of you catching and dying from the virus would be much less than the risk of you dying in a car accident

The exact details of how hard you have to squash infections to be able to keep it controlled through test and trace are probably still unclear but the principle is sound and a few countries have proven it seems a reasonable strategy

So is below scenario more realistic explanation of how testing might fit in? Changes in italics.

Educational facilities allowed open as usual. All symptomatic ppl & their HH contacts on house arrest unless they can prove they are cv19 free. Mass gatherings and travel & going to work are not restricted. Maybe masks required in crowded places and everyone encouraged to have contact tracing app on phones (*). 2m spacing encouraged by new social norms. Tests only complement this picture because they allow release from symptomatic quarantined households if you test clear, usually within 72 hours.

Anyone who has had enough (I think Singapore rule was 15 minutes close contact) contact with a confirmed case is also on house arrest for 14 days, regardless of their symptom level. (*) But no one wants the contact tracing app on their phones since it guarantees house arrest with any contact until you can prove you haven't incubated, and it takes 14 days to prove that, so the contact tracing app is a flop & almost no one puts it on their phone.

If someone thinks they know what a more realistic scenario is, please describe it.

Why testing is so crucial, why aren't we doing this?

www.straitstimes.com/world/europe/merkels-covid-19-math-resonates-thanks-to-simple-explanation

you can go to work if symptom free.

One bonus of testing (the antibody version that detected whether you have had it and are now immune ) is that you stop the spread from the asymptomatic

I suspect that "as normal" may be tempered m especially in the early days when we need to see how well our systems will work in practise

Not a definitive answer to your question, but it might shed some light on it. Graphic comparing US cities' results after the ways they lifted lockdown with the 1918 flu and subsequent hindsight is especially interesting in my opinion - and will affect my behaviour once UK lockdown is relaxed as well:

www.nationalgeographic.com/history/2020/03/how-cities-flattened-curve-1918-spanish-flu-pandemic-coronavirus/

I found this article a real eye opener:

It shows that even though there is a higher proportion of the population that has been likely experience corona virus,we are very, very far away formmore than 50% exposed.

If hospitals are overwhelemed with this low percentage of the population,it would be criminalt tell people to just go out and about likenothing is happening.