Back in March, we had ~40k new cases per day, and were seeing ~3k deaths per day.
Today, we have ~140k new cases per day, but our deaths seem to be ~1k per day, and haven't risen much with rise in cases since September.
What explains this? Were we not testing as much in March, and really our cases were ~200k per day? Or were the populations that got sick in March somehow different than today?
- the infected population tends to be younger this time around (the nursing homes already got cleaned out).
- test availability in March was low, so only the severe cases got tested
- better treatment awareness (e.g. proning).
- when the virus hit the first time, the age group of those affected was higher, hence the high initial mortality.
- hospitals have better protocols now to deal with the disease. They learned a lot over the past months wrt to treatment. For example not putting people on ventilators that fast.
- through natural selection, a milder strain has managed to be more contagious but less lethal overall.
- some of the mask ordinances were effective in reducing the viral load
If I get a higher dose of virus does that mean I will be sicker?
Yes – work on two other coronaviruses: severe acute respiratory syndrome (Sars) and Middle East respiratory syndrome (Mers) has shown this.
https://www.sccm.org/getattachment/05471bbb-2f6d-40f4-aa0e-c...
There's a number of reasons that explain the lower death rate now.[0] The population getting infected now is younger, and less likely to die. We've also gotten much better at treating patients once they're sick enough to wind up in the hospital.
[0] https://www.nj.com/coronavirus/2020/11/fewer-in-nj-are-dying...
We've also learned how to treat severe cases better. We have a few therapies now that we didn't then like remdesivir and antibody serum, and know when & when not to use them. But mostly we know what doesn't work well, like hydroxychloroquine and early aggressive use of ventilators.
The populations exposed are also shifting. Schools are back, more elderly and at risk are taking proper precautions.
1) Most mild and asympthomatic Covid-19 cases were mostly ignored back in March 2020.
Now more Covid cases are, actually, tested.
That is why "new cases" are significantly higher.
2) Big share of the population already has immunity against Covid-19 (because they were exposed to Covid earlier this year).
That is why deaths from Covid are much lower.