2020-04-22 - The COVID-19 numbers are not what you think

Given the seriousness of the COVID-19 pandemic, it's amazing how bad our metrics are. We really don't know much about the epidemiology of this disease.

Following is a laundry list of problems with the various metrics that are bandied about in the press...

Chinese numbers are just propaganda. The Chinese claim to have about 85,000 cases and 4,600 deaths. (Google dashboard) This is the recently increased set of figures, where they increased the number of reported Wuhan fatalities by 50% in the hopes that people (at least Chinese citizens) will believe the new lies, because nobody believed the old lies.

The figures don't make any sense:

Confirmed cases are not the same as community cases. Every jurisdiction is struggling with testing capacity, and prioritizes tests for symptomatic people, and often those who have had contact with a known infected individual or recent travel. That means that lots of people who are positive are not tested and do not count towards to the total reported number of cases. Moreover, it seems that lots of people are asymptomatic or pre-symptomatic.

Depending on the test capacity of a given region, there is some multiplier to go from confirmed cases to actual community cases. A recent antibody study with a somewhat random sample in Santa Clara placed this multiplier in that jurisdiction at somewhere between 50 and 85 (MedRxiv.org).

In regions where a lot of testing has been done, per-capita, this multiplier might be lower. Say 10x or 20x. In regions with essentially no test capacity, such as developing countries (India, Egypt, etc.), the multiplier will be much higher -- say 1000x.

World-wide, there have been almost 3 million confirmed tests as I write this. Much of the world is low income, so the average multiplier will be high. Assume 50x as a very conservative multiplier. That means that there are already over 150,000,000 COVID-19 infections world-wide. There is no way that we can ever put this genie back into the bottle.

The tests themselves are not that reliable. There are two categories of tests: (a) are you currently shedding virus? and (b) are there antibodies for the virus in your body? There are multiple versions of each of these. None of them is super reliable. Someone might test negative for the virus now and positive in an hour, for example.

The mortality rates are not what you think.

Not knowing is dangerous. Policy makers are making monumental decisions that will impact billions of people for decades, and they are flying blind. Is COVID-19 worse than season flu? Yes, certainly. How much worse? Maybe 2x. Maybe 10x. Maybe 100x. Maybe it depends on isolation measures and healthcare capacity. Nobody really knows. Are different control measures working? Some of them are supported by evidence (closing schools, restricting travel, wearing face masks, contact tracing) and some are only supported by what seems like common sense, rather than hard data (stay at home orders).

We need to gather more and better data. Are control measures effective? Are they causing more harm than good?

All of this takes work and will require much larger testing capacity. That has to be a top priority. Surely we can afford it, given the billions already allocated to economic supports.

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