Coronavirus - worldwide spread and control

Had to go to the chemist today. Manual doors and no hand sanitizer freely available to use - you have to buy a bottle.

The little supermarket has auto doors, the cafe has bottles of sanitizer on every table.

The only shop with a door you had to touch and open with no hand sanitizer freely available to use - a chemist. Exactly the place where you would think they might be a bit more aware of disease control!

 

...and, coincidentally, exactly the place where the product would be available for purchase.

 

Yes, but look at it from the point of view of a shop keeper.

Most shops don't want customers to be ill, especially if it looks like they might be contributing to that. So, if pushed by public opinion, they will take steps basically to say 'you didn't get it from here, or of you did it wasn't our fault as we provided , y and z'

But a chemist - their business is selling stuff to sick people, the more sick people they can get through the doors the better for business - so why do anything that might harm future sales by providing free hand sanitizer?

Cynical? Me?

 

Our supermarkets have signs not to touch produce unless you plan to purchase, but it's difficult to enforce. I saw a man stick a cantaloupe right up to his face to do a smell test and and then put it back.

 

Eww!

 

one could almost say 'world-beating'

 

Were the comments of the cantaloupe as to the outcome of the test recorded?

 

At the lab in my local hospital you have to use a pen (they supply it) to write your name on a sign-in sheet. There is no bottle of sanitizer on the counter next to it. When I made a comment to the employees about this they claimed they wipe the pen down between each person. I proceeded to watch multiple people use the pen one after another without it being sanitized. I coulda screamed!

 

There is an All-Parliamentary Group on Coronavirus, https://appgcoronavirus.marchforchange.uk/

One of its listed members is Caroline Lucas - see https://appgcoronavirus.marchforchange.uk/appg_details for members.

The same Caroline Lucas who is patron of the Sussex & Kent ME/CFS Society, but who isn't a listed member of the APPG for ME, https://publications.parliament.uk/pa/cm/cmallparty/200701/myalgic-encephalomyelitis-me.htm

https://twitter.com/user/status/1290968006210867200

 

As a Green Party member I should contact her. But I don't have capability to right now. I've been thinking about this for around a year now, I think. My apologies to you all. Can't make any promise to make any contact soon. Feel bad about it, but takes more brainpower than I have to make a decent letter. All I can say is I'll keep it in mind.

 

Coronavirus aftermath
From: Dr Alastair Miller, Medical advisor to ME Society, Brighton

gives their phone number and website address (as always)
https://www.ryeandbattleobserver.co.uk/news/opinion/letters/coronavirus-aftermath-2911485
(the same happened when BACME produced their guidelines for severe ME)
see:
https://www.s4me.info/threads/new-bacme-guidelines-for-severe-me.7900/

(the report is available here: https://www.bacme.info/sites/bacme.info/files/BACME Post Viral Fatigue A Guide to Management May2020.pdf)

(Dr Alistair Miller was Principal Medical Adviser from 2010-2015 for Action for ME)

 

Florida is now celebrating lower case numbers, forgetting testing was shut down for the hurricane. Today we posted *only* 7,650 new cases and 120 deaths. The weekly total of deaths still looks like it will be a new record (1,294 for the last 7 days today). Until that number heads down, I won't say we are past the peak.

State authorities are touting a lower rate of testing positivity, 8.34%. The problem with this is that they count positive tests of an individual once, while negative tests are counted repeatedly. Shutting down the outdoor locations where most new tests are done shifted the balance in favor of those who were tested repeatedly in hospitals and clinics. Independent estimates are up to 18%, and the state has not really explained where they are getting their numbers. In South Florida, where local authorities have their own dashboard to show testing results, results do not match those reported by the state for the same region. Different newspapers report different percentages, as if this were a political matter.

If you really want to find out infection rates you should do random sampling, actively seeking out people who are willing to be tested. To make this work, you need to pay for the tests and make them convenient. So far, we haven't done this. We are paying for drive-up testing, for those willing to seek this, but this is not close to random sampling.

One reason contact tracing has been underfunded and inadequate could be that when you trace contacts, and have them tested, you have a higher probability of finding positives. Money for testing and tracing was removed from bills at the same time Trump was publicly insisting less testing would mean fewer cases. If you don't want to find cases, I can guarantee you will not contain or control an outbreak.

A friend in California was trying to explain lower rates there last week. The explanation was not what he had expected or wanted. They were counting by hand.

The third major state contributing to national COVID-19 numbers at present is Texas. I'm not ready to pass judgment on what is happening there, except to say that it is not clear from the data that different counties are in the same country, or perhaps on the same planet. Maybe some counties have seceded from the 21st century.

This level of confusion is itself a serious problem for epidemiology.

 

While I will agree in the sense that one virion inside a cell can cause infection, the probability the virion will survive to reach and enter the cell is lower than 1.0, so the probability of an infection innate natural defenses cannot counter goes up rapidly with the number of virions transferred between people. That is why masks protect the person wearing them, and not just other people the wearer might expose to his/her own infection. It isn't a perfect defense, but we are regularly seeing the difference masks make in lowering transmission rates. The same can be said about the 2-meter rule.

 

They are predicting 300,000 deaths in the US by December.

 

Disclaimer: I have no medical knowledge and am not a scientist.

I suppose this ties in with what I was pondering, a thought experiment. Suppose someone experiences an event where, say, 10 virus particles enter their body and take hold. I assume the viral replication within the body is essentially exponential growth, and in the first few days the viral load is relatively light. But after a given incubation period, lets say 5 days, then the viral load within the body will be x lets say. But if the person then has 4 more similar encounters very soon after the first one, then after the 5 days the viral load would be 5x. For lazy convenience I'm ignoring that it would not really happen all at once, but it's just illustrating the idea.

Now presumably a person with viral load 5x after 5 days would be in far more trouble than someone with x. And does the speed at which a virus takes hold adversely affect the body's ability to defend against it? A bit like a military campaign where speed of attack means the defenders don't have time to organise their defences. And in more densely packed communities the chances of repeat infection events become more likely I imagine.

Presumably repeat infection events would only be of any significance whilst the incubating viral load was still fairly small, else the newly introduced load would be insignificant.

 

RE: whether a larger dose of virus vs. a single virus particle makes any difference

There was an article in the LA Times recently with the headline, "Wearing masks could help you avoid major illness even if you get coronavirus, experts say"

I have no idea whether this theory makes sense! I'm just passing on the information.

Read the whole article here - https://www.latimes.com/california/story/2020-07-21/masks-help-avoid-major-illness-coronavirus

 

The speed of viral replication is such that repeat infection only matters, in my current view, if the infection is suppressed by the immune system, but there is not enough immune stimulation to induce a substantially increased immune response.

Within just days any repeat infections will be negligible compared to the current infection, unless that infection is suppressed.

If an infection is not quickly suppressed by the innate immune system then the adaptive immune system will be ramping up a lot, barring some kind of immune suppression. Its much harder for a new source of infection to get a foothold once that happens.

The initial viral dosage is however very important. That is why distancing, washing hands, and masks matter beyond just preventing infection in the first place. A larger initial load increases the chance that it will not be all suppressed by the innate response, and increases the base number of cells infected with the virus starting exponential growth leading to massive infection.

Going back two decades, not checking sources, one single infected cell that lyses can have thousands of new virus particles released, already inside the body. This is much larger than most sources of new infections are likely to be, barring direct blood infusion etc. So it only takes hours for a current infection to dominate the risk.

If an infection is suppressed but its by the innate immune system, and there has not been enough of an infection or enough time for the adaptive immune system to really respond, then repeat infections could really matter. Once any of those infections takes off it should rapidly dominate the risk, new infections will indeed be insignificant.

If, and I stress if, there is a major problem with the adaptive immune response, leading to decreased antibodies and decreased T cell response, then repeat infections might again be a problem. This would be some kind of immune suppression or failure.

PS One way to think of it is a very low initial infection load is similar to a live vaccine.

 

I think that is the flaw in the argument. I do not know precisely but any virus particles that survives long enough to replicate - which is the only event that matters here - t will generate thousands of daughter particles within 12-24hrs, maybe millions. A later batch of the same original number will be trivial in comparison even the next day.

The other point is that at present infection rates are something like one person in ten thousand per week. The chances of getting two lots of virus both capable of replicating must be around one in a million, even if we take into account inhomogeneity in the risk profile.

So I think the idea that meeting two lots of virus is relevant is vanishing unlikely.

The unresolved issue is whether the number of virus particles in the dose that gets going matters. The reason why masks are useful is most likely that they reduce the probability of any single virus particle surviving long enough in your body to start an infection. I think the idea that the number of particles that can multiply at the start point matters remains unproven. It may do, but if so it is probably the difference between one particle and ten thousand getting started at the same time. A cough droplet could easily contain ten thousand particles.

 

Thank you, that clarifies.

 

Thanks for that, very informative.

So what I'm still trying to fathom is why higher population density seems to increase the ratio of deaths to cases? Once someone is infected with Covid 19, why would population density then influence their chances of survival, given that somewhere like the UK has relatively high population density, very high deaths to cases ratio, yet an extremely good health system.