Testing, Infection, Mortality

Commenter ronlsb got on my case this morning for my post Schools, Hospitals, Lockdown, claiming I've changed my tune and urging that America should be reopened instanter. If not sooner:

Mark, you spent days reciting the views of health care "professionals" warning us how truly dangerous this virus is and by doing that in effect endorsing the drastic measures being foisted upon us by our bettors. [Sic. An interesting typo.] Now you seem to have changed your tune. The more we learn about how this virus has worked, the clearer it becomes that it is successful (for the most part of course) in attacking people with preexisting conditions. Leaving supermarkets to remain open around the nation with no measurable detrimental effects ought to be evidence enough to any thinking person that the reaction to this virus has been blown way out of proportion to the damage being done to our citizens. Reopen American and do it now!

I responded that I haven't changed my tune, that I've always maintained that the modeling doesn't strictly apply to the US with its unique "human geography", that I've also always maintained that the Wuhan virus is not as easily transmissible as, for example, seasonal flu, etc. All that means in my mind that I have been open to a more flexible approach--but cautiously so, because of the undoubted danger of the Wuhan virus and the lack of reliable information. Indeed, as I pointed out in Please Read This Re Covid19 Testing there has been a lot of tendentious reporting to go along with a lack of information.

I'd like to briefly follow up on that testing post by quoting a very informed comment by "brookwood" at FR--New York State Antibody Study Finds Infectino Mortality Rate At Least 5 Times Greater Than Seasonal Flu. Brookwood uses new data regarding the infection rate in NYC, which is significantly higher than the California "studies" that I cited:

Actually, 20,792 have died in New York State - see link below https://www.worldometers.info/coronavirus/country/us/

Using a 13% infection rate and 2,700,000 cases, the Infection fatality rate is .8%, 8 times higher than seasonal flu. And the .1% seasonal flu mortality rate cited is based on cases with symptoms, it does not consider infections which could be detected by blood test but produce no symptoms. 75% of regular flu is asymptomatic so the infection fatality rate for normal flu is actually .025% Therefore Covid19 is 32 times as deadly as seasonal flu. Any questions?

https://www.nhs.uk/news/medical-practice/three-quarters-of-people-with-flu-have-no-symptoms/

https://www.cdc.gov/flu/about/burden/2018-2019.html

https://www.nationalreview.com/corner/how-many-people-already-have-covid-19/

Brookwood is making the same point I made regarding the CA studies--no other disease's case fatality rate is calculated by taking random sample in the general population. That whole methodology is extremely tendentious and intended to mislead in the direction of a preferred outcome. To the extent that a comparison is then made to flu rates, the comparison is of apples and oranges.

Here are some excerpts from at least two of his links (I exclude the CDC link). First from the UK study, which dates back to 2014:

“‘77% of flu infections’ have no symptoms, say experts,” reports ITV News. 

The news is based on a large community-based study carried out in England, which found that most people with influenza (“flu”) don’t have symptoms, and even if they do, only a small proportion go to a doctor. 

... 

Participants provided blood samples before and after the influenza season, so that the amount of antibodies in the blood could be measured. They were then contacted every week so that cough, cold, sore throat, or any “flu-like illness” could be noted down. If any of these were experienced, participants were asked to complete a symptom diary and to take a nasal swab to test for the influenza virus. 

Approximately 20% of people had an increase in antibodies against influenza in their blood after an influenza “season”. However, around three-quarters of infections were symptom-free, or so mild that they weren't identified through weekly questioning. 

This is very much a “good news, bad news” story. It is good news in that so many people with a flu infection are spared the burden of a nasty infection. However, limiting the spread of a future pandemic could be challenging, as it would be unclear who is infected. 

This reinforces the importance of practising essential hygiene habits to stop flu spreading, such as frequent hand washing and cleaning surfaces so that they are free of germs – especially if there is an ongoing flu pandemic.

I understand, of course, that all those people touting the "low fatality rate" of the Wuhan virus are, at least in part, reacting to what they see as the overhyped prognostications for this pandemic. In reality, from an epidemiological standpoint there is nothing at all surprising in the fact that most people who come in contact with the Wuhan virus remain symptom free. It was always to be expected. The two main points to remember are these: 1) as brookwood points out, the Wuhan virus really is more deadly than seasonal flu, and 2) as I pointed out in the post on testing, most of those symptom free people are also likely to be immunity free. All this has to do with transmissibility, and that could change if the virus is allowed to spread freely by an unguarded "reopening", a reopening that isn't calibrated with these epidemiological considerations in mind. Especially if we have reason to believe a recurrence piggybacking on the "regular" flu season that will start up again in the fall.

Next up, from NR, How Many People Already Have COVID-19? The author starts out with some useful comments re the testing in California in elsewhere that seeks to get a handle on the prevalence of the Wuhan virus in the general population. In doing so he stresses the very real limitations on the methodologies followed. However, far more to the point, he adds:

Lastly, as numerous folks pointed out on Twitter throughout the day, New York City now has fatalities totaling more than 0.1 percent of its entire population — 0.1 percent being an important threshold because it’s the fatality rate of the flu. In other words, even if 100 percent of New York is infected and no one dies from here on out, the virus is more dangerous than the flu. So, while the fatality rate will likely be lower than expected, it won’t be too low.

Please note that--0.1% of the entire population.  That means the Wuhan virus--at least in NYC--is many times more deadly than any seasonal flu. Whether the NYC scenario can be repeated elsewhere is beyond my abilities to predict. Fortunately for the country, no other metro area has been remotely as hard hit as NYC. But that situation, even allowing for Cuomo's blunders re nursing homes and the subways, should give any responsible person pause.

(A random thought about flu comparisons, by the way: Two diseases with the same fatality rate can kill very different numbers of people. The flu kills tens of thousands each year despite the fact that about 60 percent of kids and 40 percent of adults are vaccinated and some other people have leftover immunity from previous years. If COVID-19 has a fatality rate of 0.1 percent and two-thirds of Americans get it because no one is immune, that will entail 220,000 deaths.)

So, again, I'm not changing my tune. I understand that we can't stay shutdown indefinitely as the Left is urging. I've always maintained both the differences between the Wuhan virus and the flu as well as the unique circumstances that make the US very different from other countries. I'm still urging caution and careful consideration.