Map of life expectancy at birth from Global Education Project.

Tuesday, May 19, 2020

I highly recommend this

It's a primer on epidemiology as applied to Covid-19, with interactive simulations.

It shows what happens if we do nothing, and if we take various measures against transmission, and it adds important concepts one at a time. There's a lot to take in but it's all made very clear and presented so you can grok one idea before you move on to the next.

One of the most important things to take away is that it matters how fast we get to herd immunity. Assuming there's no vaccine, that's the only realistic way out. (A permanent regime of testing and contact tracing is possible, but not much fun and it means people are still getting sick and dying, just at a low rate.) Even with that, assuming immunity is not life-long, there will be a steady but fairly low rate of infection -- i.e. the disease becomes endemic -- but we can live with that if we have to, it won't overtax the health care system.

But -- if the prevalence at the time herd immunity is reached is high, there will be what's called overshoot. There will be so many infected people that even with the reproductive rate less than one, lots of the previously uninfected people will be exposed. If the prevalence is low, however, the overshoot will be less and fewer people will get sick and die -- even if we never get a vaccine. The  way to have prevalence low at the time herd immunity is reached is to slow down the epidemic, by the kinds of measures we're taking now.

Also: No, obviously we can't continue in the full shut down mode. So we can make people's lives easier and reduce the economic harm by opening up smartly. Here's what you can do to help yourself and humanity.

1) It's safer to be outdoors. (Even more so in warm sunny weather.) What you want to avoid if at all possible is to be congregating indoors. That's why governors are starting by allowing outdoor dining at restaurants. Better to meet your friends in the park than have a house party!

2) Keep gatherings small. That's just statistics. The more people in a group, the better chance one will be infectious and the more people they can infect.

3) Whenever you do leave the house, wash your hands as soon as you get back, and if you're out for a long time use hand sanitizer.

4) Masks really do help. They do more to protect others in case you're infectious and don't know it, but they also protect you somewhat.

5) Avoid physical contact and try to keep a distance from people, but being physically close for a few seconds is not so dangerous assuming you do all of the above. It's prolonged physical proximity that's most risky.

5) If people do need to be indoors in large groups, as in a place of business, keep physical distance, wear masks, clean surfaces frequently, and insure good ventilation.

That's enough to drive R down a lot and make a huge difference.


1 comment:

Don Quixote said...

I see ignorance and a sense of entitlement as the major impediments to implementing these simple guidelines. People who feel it is their "absolute" freedumb to do whatever they want, irrespective of the rights of others. I don't know if this is a bigger problem in the USA than elsewhere, but I live here so that's where my concern lies.

As a former professional musician, I can say from experience that it only takes one idiot to cough really loudly in a quiet section of a piece of music to ruin the experience for hundreds of others. Likewise, people who don't observe pandemic guidelines endanger all those with whom they come in contact. And those are generally the people not looking for helpful information online--or anywhere else. Strategically placed cough drops don't work in the concert hall, and I think that nothing short of aggressive tactics by authorities will keep people who don't want to comply with public health in line. Something between Sweden and China's protocols might work :-)