4 ms·
There is another point too, which also to some extend goes against your point—that we model epidemiology in standard ways, and that in order to use those standa
by mikorym 7y ago
There is another point too, which also to some extend goes against your point—that we model epidemiology in standard ways, and that in order to use those standard ways we need the parameters in the set of differential equations. And these do make predictions based on the equilibria. I am not saying they solve everything, but they are routinely used to for example calculate how many people need to be vaccinated to stop outbreaks of measles.
The article does mention most of the parameters; but we don't know what values to assign to those parameters. The last scientific writing that I was reading speculated about the R_0, but I believe we are still not sure about that. In any case, the point of the parameters is to find R_0, so we cannot expect to have an accurate R_0 without them.
We also don't know mortality rates in a general population (look at Italy vs. China, when specifying to age groups). But anyway, all I wanted to say is that our models are simplistic, but surprisingly useful.
- thereisnospork 7y agoThe point of the parent is you can't actually find R_0 because R_0 depends on the behaviors of millions of people which cumulatively are based on billions of factors. R_0 isn't a constant, it's an equation. Mathematically, unless you get really lucky or have a very idealized system, the standard models underfit the actual system. The models can still be useful though, e.g. 'we must reduce r0 below r_critical to eliminate spontaneous spreading given herd immunity %'s' is worth knowing.
- jvanderbot 7y agoThis is not as absolute as is being presented. We can speak about spreads and aggregate behavioral patterns just fine if we take times to infinity and zoom out far enough. The next few weeks or localized transmisson (which is "impossible" to model) are problematic, agreed.
- jacobr1 7y agoActuaries do a pretty good job predicting things at a population level, where many factors average.
- watwut 7y agoR_0 changes as people change their behavior. It is not one constant common to all places and times with virus. Edit: people down voting this, please look at definition and those papers. R_0 does changes.
- deleted 7y ago[deleted]
- dragontamer 7y agoEven without changing behavior, R0 can change as a virus enters different conditions. The flu in the winter (aka: Flu season) has higher R0 than the flu in the summer. Even if all humans acted the same in both cases. R0 is assumed to be a constant so that the math / models work. But it really changes dramatically in practice. Maybe someone else will eventually make a model where the constant is more... constant. But until then, we will continue to use this model.
- coronqueue 7y agoHow certain of this are we (for the flu)? When I've looked into it, I've found it difficult to assess the degree to which we are looking at "behavior changes between seasons" vs "the season matters". Reasons the season might matter: Thicker air (higher humidity) may reduce particulate spread. Viral lifespan may be different under different temperatures. Yet, in researching the issue, I tend to find things like "well, in animal models, this is what we've seen". Or "we think the heat reduces the effectiveness of a protective membrane that the flu uses". Despite some effort, I've not found sources that both (1) seem reliable, and (2) provide a clear/concise understanding of what we know and why/how we think we know these things.
- dragontamer 7y agohttp://sitn.hms.harvard.edu/flash/2014/the-reason-for-the-season-why-flu-strikes-in-winter/ http://sitn.hms.harvard.edu/flash/2014/the-reason-for-the-se... They stuck a bunch of guinea pigs into a box, one box at 41F, a 2nd at 68F, and a third at 86F. The box with 41F had the highest transmission rate. The box at 68F and 86F had lower transmission rates, even 0% transmission rate in the presence of 80% humidity. ---------- No such experiment exists for COVID19 yet. But because COVID19 continues to exponentially grow in the southern hemisphere (Australia in particular), there doesn't seem to be a relationship between temperature, humidity, and COVID19 like there is with the flu.