[OnTheWarpath15]

Originally Posted by 'Hamas' Jenkins

Excellent article on herd-immunity and how vaccines affect it, R0, and fatality rate.

I would encourage everyone to read this. It also has a tool you can use to demonstrate how many people need to get the disease for herd immunity and what the total fatalities would be based upon the fatality rate.

https://fivethirtyeight.com/features...-wont-save-us/

Read it this morning, this part stuck out to me:

And reaching herd immunity as the outbreak is raging is a completely different scenario than, for example, doing so after a vaccine has been created. With a vaccine, you can immunize people before they’ve encountered the virus, so by the time the virus gets to a vaccinated population, it has nowhere to spread. But in an active outbreak, even once the herd immunity threshold is reached, the infection keeps going. It takes time for the spread of the disease to crest because, for a while at least, many contagious people will each still infect a small number of vulnerable people, which means even more people will get sick and die. It’s a phenomenon known as “overshoot.”

“The disease sort of stops increasing at the point when you reach herd immunity, but there’s still lots and lots of people infected. It only slowly goes down, and on its way down, [it] infects another third of the population,” said Richard Neher, an evolutionary biologist at the University of Basel in Switzerland. “If you drive a car and suddenly you switch off the engine, it doesn’t stop instantly.”

So think of crossing the herd immunity threshold as determining the fate of the disease (it’s now bound to die out) rather than its status (it’s dead).

Since the new coronavirus is highly contagious (meaning a large percentage of the population would have to get it to slow its spread), the human toll of reaching herd immunity without a vaccine would be staggering. And that’s assuming that once a person gets sick, they stay immune for a long time. But at this point, we don’t know if that’s the case.