Health Nerd Profile picture
Oct 15, 2021 25 tweets 7 min read
This paper came out recently, and it is HUGELY popular among anti-vaccine advocates who are using it to suggest that vaccines don't work

It's also very fundamentally flawed. I'm a bit surprised it was published. Some thoughts 1/n Image
2/n The paper is here, and it's basically a series of comparisons of publicly-available COVID case and vaccine data conducted by a Harvard professor and a high-school student (note-DO NOT BE MEAN TO THE STUDENT, NEVER BE MEAN TO STUDENTS)… Image
3/n The study is broken into 2 sections. In the first, the authors took @OurWorldInData info, comparing the previous 7 days of case data between countries by vaccine rates. They produced this graph, showing no relationship between vaccines and reported cases Image
4/n There are several fundamental mistakes with this analysis. The first one is a biggie - confirmed cases, as reported by countries, are a useless statistic by themselves
5/n This goes back to the very early days of the pandemic - cases are, by definition, a function of tests. Without tests, you don't confirm cases, and therefore this comparison makes no sense at all on its own
6/n Did this impact the author's graph?

Very clearly yes. For example, let's compare the country Georgia (5408 cases/mil) with some of the places with less than 50 cases/mil in the author's graph on case/testing numbers ImageImage
7/n So the y-axis of this figure is uninterpretable. Meaningless.

What about the x-axis? Image
8/n There are 2 ways you can become immune to COVID-19 - vaccines and PRIOR INFECTION

In some of these countries (India, Russia, USA etc) it's likely that upwards of 40% of the entire population is immune to COVID-19 because they've had the disease and recovered (or died)
9/n In other words, we might expect that in places like Brazil, where 1 in every ~350 people has died from COVID-19 since the pandemic began, there would be quite a bit of immunity even with relatively low vaccination rates
9.5/n So comparing places on case numbers without taking infection-induced immunity into account is nonsensical, unless for some reason you think that it does not prevent infections
10/n On top of this, we've got the issue of an arbitrary 7-day window. Angola looked really good if you downloaded the data on 3/09. It looks less good if you download the data today Image
11/n So the first graph is pretty much useless as evidence. What about the second bit of the analysis?

Well, the authors essentially did the same thing, but for US counties. They found no difference in cases in US counties by vaccination status ImageImage
12/n So vaccines didn't prevent cases in the US!

Except, well, there's issues here too. Let's look at the places that the authors explicitly mention in the text Image
13/n Going to the file that the authors used, from Healthdata dot gov, you can see some really weird things pop up. Chattahoochee, GA, has a population of 10,907, but has 30,233 people who are fully immunized Image
14/n Indeed, looking down the list, all three of the counties identified by name - Chatahoochee, Mckinley, and Arecibo - have vaccinated more people than live there by quite a wide margin Image
15/n Meanwhile, of the counties classified as "low" transmission have rates of vaccination not just below 20%, but close to 0%!

What's going on here? Image
16/n The answer appears, based on this excellent @jburnmurdoch thread, to be that in the US vaccine doses are recorded based on the county *where they are given* not where the person lives
17/n This actually explains those discrepancies very neatly. Arecibo Municipio, for example, contains a stadium listed as a mass vaccination site in Puerto Rico Image
18/n On top of this, we've got the same issue with picking an arbitrary 7-day window as before - the median population in a county from this spreadsheet is ~26k people, which means that small variations in case numbers make a big difference
19/n This is even more apparent when looking at those "low" transmission counties - the median population is ~1k people, with some counties having <100. Weekly variation makes a HUGE difference!
20/n For example, Mineral County, CO, pop 769 is a "low" transmission county on 9/2, but a week later on 9/9 it's a "high" transmission county because it reported...2 cases
21/n All in all, this analysis is a bit meaningless as well. Using a 7-day period is pointless, it again ignores infection-derived immunity, and the vaccine rates are clearly not correct by county
22/n Ultimately, I don't think this paper has much, if any, meaning, and it's kind of bizarre that it was published at all. It certainly proves nothing whatsoever about vaccines and their effectiveness
23/n Oh, also, these are the most basic issues in the paper. I didn't even get started on things like Non-Pharmaceutical Interventions, confounding, etc etc etc
24/n Worth noting that the authors' intentions were clearly not anti-vaccine per se, but I do think that the paper is nevertheless not sufficiently robust to actually conclude anything about vaccines Image

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More from @GidMK

Jul 1
Preprint is out for one of my favourite projects of the last year

What happened when research was retracted during COVID-19?

The answer? No one seems to care 1/10…
2/10 Along with @lonnibesancon, @Tari_Turner, and team from @Monash_SPHPM, we took the @RetractionWatch database of retracted COVID-19 papers and checked the papers that cited them
3/10 We limited this analysis to clinical papers, because they were much more commonly cited than retracted editorials, perspectives etc, and also because they tend to have a much bigger impact than non-clinical research
Read 10 tweets
Jun 30
I think what's really interesting is not the massive inflation of impact factor in big journals, but the *wild* increase in many smaller journals
For example the International Journal of Infectious Diseases - from 3.5 to *12.1*. A 4 times increase!! Image
Or the American Journal of Therapeutics, which has gone from 1 in 2020 to 3 in 2021 Image
Read 4 tweets
Jun 29
For a blog I'm writing - something that's not COVID-19

I can see at least 5 serious issues with this trial. Who can tell me what they are?…
Well spotted! The authors call it randomized but actually they just allocated people alternately to intervention and control
Dr Tim is on fire! Yes, it's called blinded but there's no description of blinding and the placebo is not described either
Read 6 tweets
Jun 26
In case you weren't aware, there are many countries fudging their COVID-19 numbers in some way. China, for example, basically just stopped reporting any deaths after their initial surge in Jan 2020
Is it plausible that China has had no deaths due to COVID-19 in the last 2 years?

No. Not even a little
This is not quite as fake as Belarus, which just makes up numbers that look good, but it is extremely unlikely that China has had no deaths at all from COVID-19 this year
Read 4 tweets
Jun 20
I have no particular expertise in this area, but from a scientific perspective I find the banning of transgender/intersex athletes with these vague arguments to be problematic
The thing to remember is that no one cares whether elite athletes have an advantage. Every elite athlete has advantages over their peers to some extent (there's a reason short people rarely play basketball)

We care about UNFAIR advantages
So, for example - without debating whether this is true or not - we consider doping to be unfair for a variety of reasons while using expensive and difficult to obtain training methods are usually considered to be fair
Read 25 tweets
Jun 16
Another fairly large RCT from Iran fails to find a benefit for ivermectin in the treatment of COVID-19. People taking ivermectin no less likely to deteriorate, non-sig less likely to die, and more likely to need hospital care than placebo…
So that's 3 more trials with no meaningful benefits for ivermectin, with a total of about 3,000 patients, reported this week. The updated meta-analysis for mortality looks less and less positive
Another fascinating note - the new Iranian trial which found no benefit was completed nearly a year ago. The same team published positive results from their pilot in April 2021…
Read 6 tweets

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