A Leading Indicator For Covid19???
Hi all — if you missed it, I’ve been posting videos on YouTube on my analysis of the CV-19 pandemic.
These videos contain a basic prediction model on when the daily case count in New York City should hit zero — originally, and giving an extra 4–5 day lag over South Korea’s timeline, I gave it by next Friday/Saturday (the 30th) at the latest.
I will now however have to again adjust this date.
Why? How?
First, recall that I noted a number of key missing variables within my model, which included:
1.) The testing rate in NYC — how many people are tested daily?
2.) The positive test rate — of the people being tested, how many are being tested positive for CV-19?
3.) And most importantly — is there a backlog of testing patients? Meaning, of the people waiting to be tested, are they told to go home and come back the next day?
This last point is particular crucial, as I discuss in my latest video, since potentially infected people who are not able to be tested can return home and spread the virus.
Second, Governor Cuomo revealed that 10k people this past Friday statewide had been tested. I assumed (very incorrectly) that at first 10k people in NYC — subsequently revised down to 5k — are being tested daily.
This does not seem to be the case at all.
IF New York City were testing thousands of patients a day, our total case curve (as well as daily case curve) would exhibit extreme convexity, shooting right up into the heavens, as more infected New Yorkers are brought to light in the data. This is what I originally predicted — 100% total case growth for 3–5 days, before hitting the zenith of daily cases. Afterwards we would be close to nearing the zenith of our total case curve.
However, currently our total case growth rate is slowing dramatically daily — from 118% to 97%, to 44%, to 43% over the last 4 days, by the latest numbers.
What gives?
Are New Yorkers effectively quarantining themselves and therefore limiting the number of infected patients? Or are we simply not testing enough people per day?
As mentioned above, I currently am unable to find any info in regards to the number of daily tests being done, or even more shockingly, any information on where to go for testing.
Then I finally went here and found some answers to my questions in regards to the supposed number of daily tests, and also why the total case count growth rate was slowing so dramatically.
As per NYC.gov Department of Health, if you have extreme flu-like (CV-19 like) symptoms, you must wait three or four days and then call your health provider if you still are not feeling well. You can go to a hospital to get tested ONLY IF your health provider allows you to. Otherwise you must remain at home. If you are still feeling very unwell, you would then call 911.
Basically, even if you are exhibiting severe symptoms, you are to stay home. (I think the most effective way to get any care at this point is to simply call 911 and say you can’t breathe. I don’t think this is how the majority of virus tests are being done — via ER — but it probably makes up a decent portion.)
This strict testing procedure explains why the growth rate in total cases has been so drastically low over the last week, and why the number of new cases should be roughly the same day over day.
It’s not that our testing sites are overwhelmed, nor is there a backlog of potential infected patients that have yet to be diagnosed.
The NYC Department of Health is simply severely limiting the amount of people who are able to be tested.
What’s the reasoning behind this?
- To ensure adequate supply of hospital beds, ICUs, ventilators and PPE.
- To only help those who are in extreme need.
I saw this tweet today by a NBC reporter and I seem to be vindicated:
However, the dangers of limiting testing are obvious: it relies on New Yorkers maintaining strict quarantine, meaning that EVERYONE — those that are exhibiting symptoms as well as those who are asymptomatic — must stay at home. More on this below.
As New Yorkers have not done a great job in maintaining quarantine (just head to your nearest public park…actually, do not), our ultimate total case count may be considerably larger.
How does our model change? (green is past data, yellow is projected)
- Incorporate a 3 day rolling average for New Daily Cases
- Based on the last 6 days, the 3 day rolling average went from 2k to 2.5k, a 25% increase
- Therefore the next 3 days we increase 2.5k by a factor of 1.2, then the next 3 day average by 1.15, etc.
- Peak daily case numbers may hit ~4k next week, before sharply declining
- Total case number still stays at ~50k
The big danger here, I must reiterate, is that if New Yorkers do not quarantine and the virus continues to spread, those with severe symptoms who have been told to stay at home as well as newly infected patients, may all call 911 at the same time.
In other words, even though the City is doing its best to limit the flow of admitted infected patients, the tap could very well break, resulting in an uncontrollable burst of pressure (i.e. the total case line would quickly turn into a wall, shooting straight upwards).
This obviously would not be reflected in the data until days later, as hospitals would be overrun. I am certain you would hear the constant wailing of sirens for 24 — 48 hours, as well as breaking news stories, before any daily numbers are updated.
ER visits’ data such as the snapshot above, are therefore a possible leading indicator of Covid19 cases.
Lastly, a big shoutout as well as supportive prayers to all the health practitioners and hospital workers, doctors and nurses, grocery store workers and pharmacists, all on the front lines of this pandemic — within New York City, nationwide, and globally.
For us New Yorkers, we can all make their jobs vastly easier if we keep healthy and stay indoors, no matter how beautiful it is outside.
Stay healthy, stay safe, and stay indoors,
Brian
