Stop the Superspreading!


                                                                                                                
One again, I’m omitting my projections of deaths because they have hardly changed at all since yesterday. This is because the 7-day growth rate in total deaths, which drives my projections, has remained at 7% for the fifth day in a row. However, I have updated all of the daily numbers shown below.

There was an excellent opinion piece in the New York Times this morning called “Just Stop the Superspreading”. It discusses how – in all countries – only 20 percent of Covid-19 cases caused 80% of infections, and points out that 70% of infected people never passed the virus to anyone else. Superspreading cases included a crowded call center in South Korea in late February/early March, where probably a single case resulted in 94 of 216 employees being infected. Other cases have included funerals, church services, bars, sporting events, etc.

These numbers point to a way to get the epidemic under control in the US, although certainly not to end it: concentrate on preventing superspreading events, by outright banning gatherings of say more than 50 people; and also ban gatherings of more than ten, without strict social distancing being in place (as in church services). This needs to be combined with lots of testing and contact tracing, but it won’t require more lockdowns.

The author of the piece points to Hong Kong as a good example of this. They have never locked down, yet with a population of 7.5 million in a very confined space, they still have only about 1,000 cases and four deaths. But they have been aggressive about preventing large gatherings (and everybody at the protests wears masks!).

Of course, the problem is that our president and a number of governors, mayors, etc. wouldn’t be at all on board with this strategy. So it probably won’t happen. This means the fall wave will be as bad or worse than the current one; meaning we’ll have no choice but to lock down nationally this fall. If I were you, I wouldn’t prepay any travel reservations.


I. Total deaths
Total US deaths as of yesterday: 106,927
Increase in deaths since previous day: 729 (vs. 641 yesterday)
Percent increase in deaths since previous day: 1% (this number was 1% yesterday)
Yesterday’s 7-day rate of increase in total deaths: 7% (This number is used to project deaths in the table above – it was 7% yesterday. There is a 7-day cycle in deaths, caused by lack of reporting over the weekends from closed state offices. So this is the only reliable indicator of a trend in deaths, not the three-day percent increase I used to focus on).

II. Total reported cases
Total US reported cases: 1,859,709
Increase in reported cases since previous day: 22,131
Percent increase in reported cases since yesterday: 1%
Percent increase in reported cases since 7 days previous: 9%

III. Deaths as a percentage of closed cases so far in the US:
Total Recoveries in US as of yesterday: 615,426
Total Deaths as of yesterday: 106,927
Deaths so far as percentage of closed cases (=deaths + recoveries): 15% (vs. 15% yesterday)
Kevin Perry and Royce Howland have pointed out that the recoveries number is inherently flawed, meaning the ratio above doesn’t have much meaning as an absolute number. However, I think it has value as a relative number. For example, the fact that the ratio has fallen from 41% in late March to 15% yesterday, which is much faster than in countries like Italy and France, indicates the US is doing something right – most likely having to do with hospitals being much better equipped to handle Covid-19 patients than they were in March. For further discussion of this issue, see this post.


I would love to hear any comments or questions you have on this post. Drop me an email at tom@tomalrich.com

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