Time to Consider Herd Immunity For New York City And The Rest Of The Country

Yesterday Governor Cuomo announced one of the worst news I heard all month long. Only 21% of New Yorkers tested positive for COVID-19 antibodies in recently administered semi-random antibody tests. The dumb media was kind of surprised by this news. One Bloomberg article said the following:

“…the preliminary results appear to confirm predictions that the virus has infected far more people than New York has been able to diagnose. It also means that the fatality rate is likely lower than implied by merely examining confirmed cases and deaths.”

Duh! My 10-year old son is smarter than these journalists who have been mindlessly reporting the “confirmed” case count as if they really indicate the actual extent of COVID-19 infections. He tells me that in our town there must have been at least 1100 people infected with the virus because the death toll stands at 11. Yet, these journalists still couldn’t get their heads wrapped around the fact that infection fatality rate is much lower than the case fatality rate that is calculated by dividing the current death count by current confirmed number of cases.

Before proceeding further, you have to read this article I wrote more than a month ago. You won’t appreciate my current predictions without reading that article.

Let’s stay one step ahead of mainstream journalists and give you the latest facts about the coronavirus.

The COVID-19 death toll in New York State currently stands at 21000. This is actually a “minimum” for the actual number of COVID-19 deaths in NYS. The correct figure is probably closer to 25000 as a large percentage of non-hospital COVID-19 deaths were gone uncounted in New York State and elsewhere.

Once you contract COVID-19 it may take you up to 12 weeks to die or recover. So, we are certain that the number of COVID-19 deaths in NYS will continue to increase through the end of June. We are probably 70-75% done which implies that the death toll in NYS will settle around 32,000.

The figures estimated by Governor Cuomo indicated that 13.9% of New York residents were infected by COVID-19 based on the first batch of samples collected. Since it takes up to 14 days for antibodies to develop, I believe this 13.9% figure will creep up towards 17-18% range as they keep collecting samples over the next few weeks.

We also don’t know the ratio of false positives and false negatives in New York State’s antibody tests, but it is likely that the percentage of false negatives is much larger than the percentage of false positives.

Overall, it looks like the number of total infections in New York State as of today will be around 3.2 million. This tells me that COVID-19’s infection fatality rate is around 1% (32K deaths for 3.2 million infections). It could be 20% more or less than the 1% figure, depending on where the actual figures end up. However, I think 1% is a nice round estimate that’s very close to the actual infection fatality rate.

Now that we have a very robust IFR estimate, we can calculate the IFR for each age group. I won’t bore you with the details (email me if you’d have any questions about the methodology), here are the results:

Click here if you are having problems with the table’s formatting.

Age Group NYS COVID-19 Deaths IFR NYState
0-9 2 0.00%
10-19 6 0.00%
20-29 58 0.03%
30-39 238 0.12%
40-49 579 0.25%
50-59 1561 0.72%
60-69 3142 2.11%
70-79 4201 4.88%
80+ 5919 9.33%
Total 15706 1.00%

As you can see from these estimates, COVID-19 is much deadlier than the seasonal flu for people above the age of 40.

What’s the smartest way to reopen New York City?

We know that COVID-19’s IFR is 1%. Current US death toll is near its peak and stands at 50K. This means as we go down the hill, the number of US deaths will reach 100K. This also means there are around 10 million Americans who are infected with the new coronavirus.

So far we sucked at testing, tracing, and isolating infected people. That’s why we were forced to implement statewide “stay at home” orders. We also suck at the implementation of “stay at home” orders. Georgia is planning to lift a large chunk of its restrictions today. Other states will follow soon. This means we won’t be able to reduce the number of actively infected people down to manageable levels (100 or less).

In New York City around 200 people were admitted to the hospitals yesterday. Since the hospitalization rate is around 5% and it takes about 10-14 days to get hospitalized, we can estimate that there were 4000 newly infected people in New York City on April 10th. And that was in the middle of a lockdown.

I don’t think we are going to have the political determination in most states in this country to reduce the number of actively infected and contagious people down to manageable levels. This requires at least another 4-6 weeks of strict nationwide lockdowns, and desperate people are already protesting against lockdowns. The number of job losses already exceeded 26% and our GDP is on its way to register double digit declines. We even experienced negative oil prices which crashed the United States Oil Fund, LP (NYSE:USO). Even though the S&P 500 Index is down only around 13% year-to-date, that’s mostly because of bailouts and trillions of stimulus spending pumped into the system.

Enter Herd Immunity

Coronavirus Herd Immunity

This means our next best strategy is mitigation and herd immunity. For herd immunity we probably need around 50-60% of New Yorkers infected with the virus. Currently 21% of New Yorkers are already infected. This figure is probably closer to 25% for the reasons I explained above.

Nearly 53% of New Yorkers are under the age of 40. We can allow these younger New Yorkers to go back to their normal lives, get infected, and get closer to developing herd immunity. Obviously, “going back to normal” has to be optional for people under the age of 40. These people accounted for only 2% of deaths in New York State. Even if all of them are infected at the same time and hospitalized at the same time, this won’t restrain our healthcare system in any significant way.

Around 25% of the people above the age of 40 are already infected with the new coronavirus. Assuming that they are immune to the virus or they will likely survive a second infection, we can also allow these people to go back to normal as well.

Overall, nearly 60% of New Yorkers can resume their lives and the rest should have the option to isolate themselves until herd immunity or a viable treatment option is developed.

Herd Immunity For The Rest Of The Country

The rest of the country is far from herd immunity. Nevertheless, they can follow the same strategy of returning people under the age of 40 back to their “normal” lives. This will build a wall of immunity against the spread of the coronavirus in October and November.

Our estimates show that only about 2-3% of the rest of the United States is infected with COVID-19. If we can bring this figure to 20-30% throughout the summer by letting younger people contract the virus and build immunity, we might be able to reduce its R0 below 1 in September by employing an aggressive test-trace-isolate strategy.