Originally Posted by
OldnGrounded
Could you elucidate, please? What are those ways?
O'nG,
K, FWIW.....
Our study also suggests that by reducing the average infectious period to <2.3 days, the resulting will decease to a value less than 1, meaning the epidemic can be effectively controlled.
. Prior reference [5]
Estimate of incubation time gives a start point to the problem (prior reference [3])
An individual has a point in time when they are exposed, they then go through the process of incubation, and at some point in the incubation period two things may occur, the immune response to the virus will result in symptoms of an infection, and at some point, the virus will be able to be transmitted to other hosts. The concern with 2019-nCoV is that there is possible early transmission at a point where there are no symptoms, and if so, screening is not overly effective. Whether that really is the case is still open to investigation, that being one of the german cases. In the end, the problem is that the symptoms may be undetected and that complicates the issue. The surface contaminant transfer vector is often a significant cause of infection, and there is no information as yet on the survival time for this virus outside of a host. There will be a time that it can survive, at least as long as the medium it is in, saliva etc, is viable. It may be much longer, virus can survive in pretty hostile conditions as a viable structure.
Below, the time series of the patients history shows some cases which give a basis for a minimum period to go from:
- high likelihood of no exposure (GREY)
- to being exposed (WHITE)
- infected but asymptomatic (PINK)
- to being symptomatic (PURPLE)
- to being confirmed (BLUE)
In the asymptomatic (pink) to either symptomatic (purple) or confirmed (blue), we have the potential to spread. The current stats suggest that there is a large background number of cases that exist that are asymptomatic and not counted or known, and a number of cases being symptomatic but not reported, for various reasons, from privacy concerns, lack of recognition etc.
from reference [3]
The same reference document as above gives the following CDF curve. That can also be described with a distribution spread, which follows in the box plot comparing this virus with prior virus outbreaks. Whether the virus can be transmitted in the asymptomatic case or not is functionally immaterial. As the local environment and population you are within has a level of risk of exposure that is dependent on where we are on the vectors to date, unless you have spent that last few weeks in Antarctica, a boomer or an ICBM silo, the extended contacts that have already occurred since late December 2019 have a risk of exposure around you already. If's high in Wuhan, it's not zero in Reno, El Paso or Rome (the other one, in Italy). Due to that, infection control by the individual is necessary to reduce the possibility of contracting the virus, and possibly being a vector for spread.
back to the premise of stopping the spread by reducing the average infectious period to less than 2.3 days, that suggests the pink to blue part of the time series above needs to be altered. To do that, when the pink period alone exceeds the required 2.3 day period, then that indicates already that the solution is infection control. To achieve infection control, the tools available are:
- Droplet Control: (you outbound: any surgical mask, inbound to you: n95 or higher filtering), and separation from droplet sources. (avoid concerts, pubs, tax audits, the dock at the old bailey, hospitals, and... your work space with other people, and... schools. Kids are a factory for spread of anything, from jam and peanut butter to knits, and viruses.
- Surface Control; every surface you touch has a history of prior contacts, and should be considered to be contaminated. Being contaminated itself isn't the problem, can't easily stop that, but you can stop the consequences. Intervene with gloves, surface sanitizers, surface cleaners, er, UV... etc... read the stuff on your chlorox wipes and your other anti viral cleaning agents. Stopping the real problem which is the transfer from your hands to your face and membranes takes diligence or obstruction by masks... Even if the droplet is not the problem, at least having a surgical mask will act to prevent some hand to face contact. (put on a helmet and see how long you go before you want to remove it to scratch, pick, rub etc your face and bits attached so elegantly. ( Space Balls/Morons from outer space.
)
- Isolation. The lower contacts you have the fewer occasions you have to be good at what you do. There is a balance between being effective and being reasonable. Going to a concert or pub is an exposure risk. going to the supermarket once a week is a manageable exposure. There is no need for the TEOTWAWKI survivor scenario; with reasonable and simple practices, services can continue, but they need to be deliberate in their protocol application, and anyone involved needs to assume that only one person cares about your welfare.
- Time to normalisation is dependent on getting the exposure down far enough so the outbreak dies out, or the virus is attenuated by mutation (good luck with that one, it was the outcome in The Andromeda Strain, not sure of any real world case that has occurred), or that herd immunity is established naturally, (takes time) or by developing an immunity from finding a vaccine magic BB. All things shall pass... Add the infection time to the end of last infections, + the maximum time to develop to confirmation, and hey, thats over, get on with the search for Trumps foibles.
Just add water.
The question of transmission while asymptomatic arises from one of the German cases. The traveller from WooHoo gets Schweinhock and kartoffel in Germany, and then returns to WooHoo, and gets symptoms after their return.
Ein Arbeiter, den ich Zeit damit verbringe, gute Arbeit für das Wohl meiner Meister zu leisten, back in Germany gets sick; dies ist in der Tat bedauerlich und sollte in einem perfekten System nicht passieren. So, unless the symptoms were so mild they were missed...,
in fact, who cares, the carrier in this case wasn't aware they were sick, no one was, until they got back to WooHoo, back on the other side of the rock. The minor issue is that the carrier could have been contagious on the flight out, certainly was on the flight back, and everyone involved was doing their own thang, gittin' on with stuff as we do, scratching noses and shaking hands in at least 3 airports, buses, customs control points etc. etc. etc.
(there is also a silver lining in this case... as an experiment, the peeps all involved in this event would have an illness uptake over time that would eventually give a good idea on the real level of transmission that exists. It just takes time for that to occur, and it also takes the "volunteering" of the guinea pigs in this epidemiological study. It also gives more information on the age/health/sex/ethnicity sort of variables by circumstance)
By reports for the last month, it is a sub set of all that have the virus that get symptoms to the extent they seek medical assistance. The time to seek medical assistance also has changed which is good, the time series shows that. A problem is that as the number of cases increases the time to diagnosis will stop reducing and start increasing again, and as a natural response to frustration, peeps that are sick will just not bother to go to the doc/vet etc. As medical staff get sick, they are at the epi-center of the problem, then delays would tend to increase without active measures. China builds hospitals, excellent, but they need docs, nurses, cleaners, blood sucking lawyers etc....
Most protocols include administration and other warm fuzzy stuff, which is definitely needed from the societal response, but for the individual, the need is to remain informed, so "cunning plans" can be made and messed up appropriately.
with apologies to E.B.Browning...
How do I love thee? Let me count the ways.
I love thee to the depth and breadth and height
My soul can reach, when feeling out of sight
For the ends of Being and ideal Grace.
I love thee to the level of everyday’s
Most quiet need, by sun and candlelight.
I love thee freely, as men strive for Right;
I love thee purely, as they turn from Praise.
I love thee with the passion put to use
In my old griefs, and with my childhood’s faith.
I love thee with a love I seemed to lose
With my lost saints,—I love thee with the breath,
Smiles, tears, of all my life!—and, if God choose,
I shall but love thee better after death.
Baldrick: Well, I have a cunning plan, sir.
Edmund: All right, Baldrick — for old time’s sake.
Baldrick: I have a plan, sir.
Edmund: Really, Baldrick? A cunning and subtle one?
Baldrick: Yes, sir.
Edmund: As cunning as a fox who’s just been appointed Professor of Cunning at Oxford University?
Baldrick: Yes, sir.
Voice: On the signal, company will advance!
Edmund: Well, I’m afraid it’ll have to wait. Whatever it was, I’m sure it was better than my plan to get out of this by pretending to be mad. I mean, who would have noticed another madman round here?