Fitch said:
Skillet Shot said:
Cyp0111 said:
Houston did a good job of slowing this thing. It's the gov't and population working together. Masks and social distancing works.
It is difficult to identify the mechanism for the virus slowing.
- Virus running it's course after massive protests; approaching herd immunity/viral burnout
- Closing of bars
- Mask mandate
I'm hoping it's option 1. There are ~86,500 confirmed cases in Harris County with a population of 4.713 million yielding 2% infection rate. If there are 5-10 times more cases than reported, then the county may be near the 10-20% infection rate, which some have argued is the threshold for viral burnout/herd immunity due to T-cell response.
We're not approaching burnout or broad population immunity. The reports that posit that idea come with a rather large asterisk of sustaining social distancing and control measures perpetually until the bug dies out because of lack of hosts.
We are (thankfully) seeing the effects of control measures and personal responsibility kicking in after the triple whammy of Memorial Day shenanigans, bar reopenings and protests.
Burn out is really just pushing R below 1 by decreasing the susceptible population, possibly with measures in place.
For the vaccinated diseases, we talk about herd immunity at ~95%. First, many of those are far more infectious, so R0 is considerably higher. Second, we talk about outbreaks of tens of individuals at a time. A school has a dozen kids with measles and everyone goes crazy. 2019 was a measles outbreak with <1300 cases in the US.
For COVID, I don't think we need that level of reduction to get back to normal. We already start with a lower R, and clearly the current combination of masks, no bars, and already exposed population has us well below R=1. As the level of immunity increases, the masks and other factors will have less of an effect. 50% reduction from 2 is big, 50% reduction from 0.5 isn't as important.
But what is the goal?
If the goal is a low level of infection without significant additional burden on hospitals, maybe we can achieve that with R=0.9 after we bring the number down, or maybe 0.7 or 0.5.
If the goal is tens of infections per year, we are going to need to get closer to that "herd immunity as a function of R0" metric that everyone pegged at ~70% early on. And really, the only way to get there from 20% is to continue to have a low level of infection or wait until a vaccine and force everyone to get it.