Coronavirus: Hypothesis expanded.

The previous post noted the error that results from assuming uniformity in the way the virus spreads, who it affects, and what interventions are effective. There ore scraps of evidence and anecdotes that can be used to support diametrically opposed arguments. The current assumptions that underlie response to the coronavirus appear to based on the following assumptions:

1. The virus is highly contagious;
2. Everyone who has not already been infected has the same risk of contracting the infection in the absence of mitigation procedures;
3. Testing is somehow therapeutic, in that it allows for more targeted isolation practices and interventions;
4. Isolated observations are representative of universal facts.

This last one is responsible for vacillations such as wearing masks is pointless, wearing masks is potentially helpful, wearing masks is mandatory.

The assumptions noted above are worst-case defaults. They almost certainly do not reflect, nor explain the observed facts. An alternative hypothesis was suggested earlier based on a couple of assumptions that seem to be valid throughout a wide swath of nature. These are:

1. All natural phenomena operate about points of equilibrium, and when disturbed, seek new pints of equilibrium.

2. Equilibrium states are functions of environments; they are determined by how a particular phenomenon, such as spread of a virus, interacts with the immediate environment.

This post expands on thoughts previously discussed here
 https://z9z99.blogspot.com/2020/03/coronavirus-couple-of-thoughts-on-model.html
and here
https://z9z99.blogspot.com/2020/03/coronavirus-iv-hypothesis-as-to-what.html

The relatively low absolute rate of infection observed in almost all populations reflects a scenario in which the points of equilibrium exist at correspondingly low percentage of the population, typically less than 1%. This does not mean that the infection stops when 1% of a population is infected; it means that the rate of spread slows, naturally such that the number of active cases (deaths minus resolved cases) is relatively constant.

Point 2 above is instructive for purposes of mitigation efforts, and economic decisions and so forth. The equilibrium point is a function of the environment and the environment in turn is affected by mitigation efforts. If mitigation efforts are relaxed, the virus will not rage uncontrolled, it will seek a new point of equilibrium until some other environmental factor (such as vaccination, weather effects of viral survivability, etc.) changes it again. The reason that the experiences in New York state are different than the experiences in Washington state and that the experience of Sweden is different than that in South Korea, is that each of these is a different environment, with the virus tending to spread according to a locally-determined point of equilibrium. The environmental factors include genetic make-up of the population, cultural habits, mitigation efforts, crowding, transportation infrastructures, etc. The idea of an equilibrium point helps explain the relatively constant number of new daily cases in South Korea.

If the discussion of equilibrium points seems a bit hand-wavy, consider an extreme example. Assume that a hiker is passing through a forest in which some animal harbors a virus capable of infecting humans, but has not yet done so. The hiker comes into contact with the virus, is infected and dies a couple of minutes later. The virus stops replicating in the deceased hiker and he spreads it to no one else. The epidemic ceases. In this case, a point of equilibrium has been reached.

Another key point is that micro-environments are associated with different points of equilibrium as well, and that these do not necessarily generalize to larger populations. Thus, the environment on the Diamond Princess has one point of equilibrium, the choir in Washington state in which more than half of the members were infected, and the town of Vò, in which 2.9 percent of the population tested positive as the contagion was rampaging in Italy, can be explained without portending dire consequences for the wider world.

Another premise used to explain the observed behavior of the virus is that there is a gradient of resistance to disease spread that steepens as more people are infected. As mentioned previously, this is a generalization of the phenomenon responsible for herd immunity. Not everyone has the same susceptibility to the virus at the same time and for the same type of exposure. It is the distribution of this degree of resistance throughout a population and within a particular environment that determines the points of equilibrium. This was true for the plague of Justinian, the Black Death, the Spanish flu epidemic, SARS, H1N1, the Haitian cholera epidemic, etc., and it will be likely be true for the Wuhan coronavirus.