07/17/2020
The Atlantic has an excellent article on herd immunity and whether it might be lower than the 70% of the population that has been talked about. It all depends on us!
Here's the link to the article: https://www.theatlantic.com/health/archive/2020/07/herd-immunity-coronavirus/614035/?utm_source=share&utm_campaign=share
And here are some excellent quotes:
This is not the case when a virus is spreading in the real world. Instead, the complexities of real life create what modelers refer to as heterogeneity. People are exposed to different amounts of the virus, in different contexts, via different routes. A virus that is new to the species creates more variety in immune responses. Some of us are more susceptible to being infected, and some are more likely to transmit the virus once infected. Even small differences in individual susceptibility and transmission can, as with any chaos phenomenon, lead to very different outcomes as the effects compound over time, on the scale of a pandemic. As Gomes explains, “There doesn’t need to be a lot of variation in a population for epidemics to slow down quite drastically.”
For all the mysteries of how this virus affects our bodies and immune systems, and all the heterogeneity involved in the complex modeling of outcomes, Bansal believes that heterogeneity of behavior is the key determinant of our futures. “That magic number that we’re describing as a herd-immunity threshold very much depends on how individuals behave,” Bansal says, since R0 clearly changes with behaviors. On average, the R0 of the coronavirus currently seems to be between 2 and 3, according to Lipsitch. But if we all sealed ourselves in isolation pods today, the R0 would drop to zero. There would be no more deaths.
“COVID-19 is the first disease in modern times where the whole world has changed their behavior and disease spread has been reduced,” Britton noted. That made old models and numbers obsolete. Social distancing and other reactive measures changed the R0 value, and they will continue to do so. The virus has certain immutable properties, but there is nothing immutable about how many infections it causes in the real world.
We have the wealth in this country to care for people, and to set the herd-immunity threshold where we choose. Parts of the world are illuminating a third way forward, something in between total lockdown and simply resuming the old ways of life. It happens through individual choices and collective actions, reimagining new ways of living, and having the state support and leadership to make those ways possible. For as much attention as we give to the virus, and to drugs and our immune systems, the variable in the system is us. There will only be as much chaos as we allow.
The portion of the population that needs to get sick is not fixed. We can change it.
