This chart shows the transmission rate.  It is quite low and active cases are falling.  Note that the data fit the LOW or MODERATE profile since May 15, not the fast profile.

This chart shows the mortality trend.  It is down at a similar rate to hard hit countries.  It started high and increased a couple of times, and mortality is still higher in NY than most places.  It is advantageous to put off cases.  Whether the trend continues is uncertain.  But there is room to improve by just matching other regions, unless climate or demographics are responsible?

This is the slow-recovery option, putting off cases as long as possible by maintaining the current status quo.  Cases in NY nearly vanish, but not quite.  There is a small rebound in spring and summer, but it is controlled by vaccination.

This is the moderate-recovery option, which was difficult to develop for NY.  Cases are so low that moderate unlock now tends to cause large rebounds later.  This profile manages to keep the later rebound small.

Open with Dyske's online interactive model.

This is the fast-recovery option, but for NY it does not mean more people get sick right away.  It means there is a rebound in the middle of winter.

This chart is a comparison of economic recovery (on a scale of a percent of one year lockdown costs, green bars) and cost of the pandemic in direct deaths* (as a percent of the highest case, dark bars).  No relative comparison is implied at this scale.  If a person loses their retirement savings, if ten people lose their retirement savings or small businesses, how many disease deaths is that morally equivalent to?  This we feel should be a persona choice, not legislated by government.

No inflection point is evident in this chart.  The choices are on a continuum.  NY can double their economic recovery for about a 20% increase in critical cases.  Any of the recovery options are pretty reasonable for NY.   Most of its problems are in the past.  It merely needs to be wary of an inadvertent rebound.

* Deaths scale inverse to case ratio.  Case ratio is not well known.  Calculations assume 15.

SUMMARY POINTS:   The New York R₀ under lockdown is extremely low, indicating a combination of a very careful population and significant progress toward herd immunity. 

The sims were run with a case ratio of 12 corresponding to test results they released nearly a month ago.  This corresponds to just over 20% of the population having had COVID-19, compared to around 2% of the US as a whole.  See details of NY social distancing at right.

With an increasing herd immunity factor and a seasonal factor around 80% in the summer (vs. 87% in May), NY can give up half of its social distancing at no penalty, keeping R₀ below 1.0 and reducing cases.  By fall herd immunity will be enough it can afford some additional unlock for school.  The trick, with such small case numbers and so much herd immunity and changing seasons, is to avoid overshoot and avoid excessive lockdown that pushes rebounds into the vaccine period.  Vaccination is not complete until early 2022 in any realistic scenario.  These scenarios were the hardest to do without overshoot and rebound of any I've done so far.  But with very careful management NY can come back to life.

Avoiding winter rebound in NY is a bit like avoiding summer rebound in Brazil.

CASE RATIO, SEASONALITY, SOCIAL DISTANCING, HERD IMMUNITY AND R₀ FOR NY: 

We know from the rest of the US that social distancing alone will knock R₀ down to about 1.0.  NY was clearly reading around 0.8 from early to mid May before any unlock.  We can calculate the current R₀effective as a product of

* unfettered R₀natural (about 2.5, from the start of the R₀ tracking chart 3/21 and prior)
* seasonal factor S (from various papers, climate only not school, 87% for NY in May)
* herd immunity factor H, which at 21% infected/resitant is H = 100%-21% = 79%
* social distancing factor D (which we will derive)

R₀effective = R₀natural * S * H * D
0.8 = 2.5 * 0.87 * 0.79 * D
=> D = 46%
(social distancing factor or reduction in contact rate in NY, full lockdown)