10 thoughts on “Case rates amongst vaccinated vs. unvaccinated people: Miller Report for August 31, 2021 (column)

  1. Population of Mendocino County appears to be 91,600. If 49,600 people are vaccinated, that means 42,000 unvaccinated. If 945 unvaccinated people have Covid, then, by Miller’s logic, that means that “unvaccination” has an “efficacy” of 98%. Back to the drawing board, Miller.

    • Traber’s comments on Dr. Miller’s article are a bit misguided. (Dr. Miller’s responses were tactful and I’m sure he had to get back to the ER, so I’ll try to unpack the main points of his article.)

      First, what is really important is Dr. Miller’s comparison of recent un-vaccinated versus vaccinated hospitalizations. Since the “Delta variant” hit Mendocino County around July 26 of this year, 1060 people went into the hospital with Covid. Out of those 1060 seriously ill people, 945 were unvaccinated. 115 were vaccinated. Do the numbers: 89% of the people hospitalized with Covid since July 26 were unvaccinated. Only 11% of the hospitalized Covid patients were vaccinated.

      So not being vaccinated creates a pretty big risk if you get sick with Covid. If you aren’t vaccinated and get Covid you are 9 times more likely than a vaccinated person to get sick enough to land in the hospital.

      Next let’s look at deaths. 14 out of 17 people who died of Covid in the hospital since late July were unvaccinated. In contrast, only 3 of the 17 who were vaccinated died. (They were also very old and sick to begin with, while several of the unvaccinated deaths were under 50 and healthy.) Do the math: if you are unvaccinated, get Covid and end up in the hospital your odds of dying are at least 4.5 times that of a vaccinated person — probably more given that the three who died were very old and already sick of other illnesses.

      Last, let’s look at Traber’s 2% calculation: what it shows is how many un-vaccinated people have become sick with Covid as of August 26. The 2% does not represent either (1) your risk of getting Covid if you’re not vaccinated, and (2) more importantly, your risk of ending up with a serious case that puts you in the hospital and increases their risk of dying.

      The basic problem with Traber’s 2% number is that it represents a snapshot in time: 945 out of 49600 unvaccinated people have gotten Covid since July 26. But that does not mean that an unvaccinated person’s risk of getting covid is only 2%. If fact, it is totally irrelevant to that risk. It just means that only 2% of the un-vaccinated have gotten covid in the last six weeks. As time goes on, more un-vaccinated people will get sick and Traber’s percentage will rise. As total infections rise, the percentage of 2% will rise as well. For example, when another 500 unvaccinated persons get covid, TThat isn’t a cap either. Add another 1000 unvaccinated cases and Traber’s number will be 5%.

      So here’s the important point Dr. Miller was making: way more people who aren’t vaccinated will get Covid than those who are. Many, many of them will get sick enough to go to the hospital, compared to vaccinated people. If they are in the hospital many more will die.

      It’s up to you, I guess, to take the risk. But it doesn’t seem like it’s worth it for two little pokes in the arm and a sore arm or (rarely) a day or two in bed.

    • Sorry, I missed some words in a sentence near the end.
      It reads ” For example, when another 500 unvaccinated persons get covid, T”
      I meant to say ” For example, when another 500 unvaccinated persons get covid, [Traber’s] number is 3%.”

    • By the way, I don’t mean to criticize Ivor Trabor, whose comment below indicates that he is trying to educate the vaccine-hesitant, as am I. So if some of it reads that way, Ivor, please accept my apologies.

    • Tim, thanks for commenting. I see that my point wasn’t clear, which was that “efficacy” is a technical term in epidemiology, and it is NOT the percentage of vaccinated people who haven’t tested positive. Rather, efficacy is measured by comparing two groups that have received DIFFERENT treatments (vax/unvax), not comparing two groups who received the SAME treatment (vax) and tested differently (pos/neg). Efficacy is typically measured in a clinical trial, where exposure and testing is controlled, with some receiving a placebo and some the vaccine. If you want to stretch the meaning of “efficacy” to the uncontrolled data of Mendocino County residents (where exposure and testing is largely unknown) you get an approximate “efficacy” for the vaccine of 1 – (210/49600)/(945/42000) = 81%. When trying to convince skeptics, we need to be correct with our details, not sloppy or confusing. Thanks for listening. Best wishes to you as well.

    • Here’s another example of what I mean by being correct with our details: If, in a sample of 1060 Covid-infected people, 945 are unvaccinated and 115 are vaccinated, and 14 unvaccinated people died while 3 vaccinated people died, can we then conclude, from THOSE figures, that unvaccinated infected people are, in general, 4.7 times as likely to die as vaccinated infected people? No, we cannot. In this small sample, it’s actually the other way around: 3 out of 115 vaccinated people (2.61%) is 1.8 times higher than 14 out of 945 unvaccinated people (1.48%). The lesson here is: don’t draw general conclusions from small samples. There is plenty of data available in the world that shows that being unvaccinated is considerably riskier than being vaccinated, but trying to convince local people of this by using small data sets from the local setting is not the best way to proceed.

  2. Miller also said: “Our county public health officer… confirms that of the 1,060 new cases since July 20th, 2021, the start of the current surge, 945 (89%) were in unvaccinated persons and 115 (11%) were vaccinated.” And then, four paragraphs later: “Since July 20th, 2021, there have been only 210 vaccinated persons test positive for COVID.” Well, which is it? 115, or 210?

    • Ivor, thank you for catching that discrepancy. I am glad to see you and others are reading what I write. I will try to do better in proof reading before I hit send. While it is no excuse for sloppiness, I was really exhausted when I wrote this.

  3. Hi Dr. Miller. Thanks for reading and responding to my comments. (Now I can tell everyone I’m “famous”!) Rest assured I have no desire to refute your report in general. I am in favor of the Covid vaccine, and I am opposed to false conspiracy theories. I’m just a guy who fixates on small errors, and then often forgets to ALSO comment on the larger picture. Your report was brought to my attention by a vaccine-hesitant person in your county, and I was worried that the errors in the report could actually lead to the OPPOSITE of your intended purpose. Meanwhile, I see now that the Mendocino County Covid Dashboard ALSO misuses the term “efficacy.” (I guess it’s going around, like a virus.) I know nothing about you, and not much more about MCDH (I moved from Ft. Bragg to Canada a decade ago) but I’m a big fan of medical professionals, so I salute you and the work you do, and wish you all the best.

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