how much longer do we have to go with this?

with forty million confirmed cases globally, the actual number is something more like 600 million, as a lower bound - that's 7.5%. the seroprevalence to crude case count ratio has mostly been measured in advanced countries, and seems to be somewhat less than ten, but the spread is global and you would expect that ratio to be much higher in most of the world, so a factor of 15 is no doubt an underestimate.

so, we're probably pushing close to a 10% infection rate, with the vast majority of those people showing enough symptoms that they can expect to develop an immune response.

now, this is going to be very localized, with some regions having high levels of immunity and some regions having low levels of immunity. you should be able to loosely measure this by how hard the region was hit.

a reasonable estimate for the actual case count in the united states right now based on empirical data is roughly 40 million, which is 12% of the population. it seems that the magic number to drastically slow the spread is not 70% as previously thought but rather 20%. while regional variations in the united states will dominate, it would seem to be halfway there, overall.

we could of course stop this with a vaccine, if we can get one first. but, if we're halfway there, and the growth rate is an increasing function, that would suggest we have less than six months to get there before it burns itself out. three, probably. it's going to peak in september...

our governments have all spent a lot of money on these vaccines, but they may find themselves arriving to a muted threat.

that's not to say that this thing won't be dangerous for years to come, or that it won't continue to spread in much the same way that it does now, albeit at a reduced rate. it will still be out there, and the vulnerable will remain at risk. when the vaccines get here, the elderly and at risk should take them immediately.

it's just that 20% immunity seems to be enough to stop the actual pandemic.

i think people maybe have this binary view of herd immunity, but this isn't quantum physics, we can have continuity, here. herd immunity is an inflection point, but the reduction in spread will increase proportionally with the number of people infected. so, 70% is better than 50% is better than 20%. but, the magic number for the health system seems to be a lot lower than previously thought, making the concept a lot more attainable than previously imagined.

the same rough calculation produces less than 5% immunity in canada, as a whole, indicating that we have much further to go. but, we will still probably beat the vaccine to substantive immunity, in the end.