Health Nerd Profile picture
Epidemiologist. Writer (Slate, TIME, etc). ' Research fellow at @UoW Host of @senscipod Email gidmk.healthnerd@gmail.com he/him

Sep 10, 2021, 13 tweets

This graphic has been passed around a lot by the ivermectin crowd, so I thought I'd very briefly explain why it's quite clearly incorrect 1/10

2/10 The graphic is based on this preprint on medrxiv, which appears to make several mistakes that lead to a lack of much meaning in the final outcomes of the analysis

3/10 The basic idea of the paper is to split countries up by their use of ivermectin to treat river blindness, and then compare them based on COVID-19 deaths

There are two main issues with this

4/10 The first problem is the exposure data - saying "these countries have been treated for endemic onchocerciasis" doesn't actually make any estimate of how many people took ivermectin in 2020/21

5/10 If you look at scientific publications into onchocerciasis, it looks like ~90million people across Africa used to receive ivermectin yearly for this purpose i.e. journals.plos.org/plosntds/artic…

5.5/10 However, this mass-distribution of ivermectin for river blindness by the WHO was PHASED OUT IN 2008-2015. There are individual programs ongoing, but it is not correct to use past estimates of endemic disease to classify countries
who.int/about/evaluati…

6/10 Conversely, the WHO does still assist in distribution of ivermectin under a program to eliminate lymphatic filiariasis

This includes countries labelled "No ivermectin" in the above graphic
who.int/publications/i…

7/10 So the exposure is meaningless - this chart is comparing countries that use ivermectin to...countries that ALSO use ivermectin on a mass scale

But the outcome is wrong too

8/10 We KNOW that the death data in many African countries for COVID-19 is not great. For one thing, some countries simply do not record any COVID-19 deaths (or test for COVID-19 at all)...

9/10 ...for another, scientists in Zambia have PROVEN that the death data there is a drastic undercount. Comparing places is more about who records deaths better than any meaningful attribution of causality bmj.com/content/bmj/37…

10/10 To sum up - this graphic is meaningless. Neither the exposure OR the outcome are correct. Many people in the orange countries received ivermectin, and many more people than recorded in the blue countries likely died of COVID-19

11/10 One minor addendum - this took me a total of about half an hour to check. The study itself is simple, and looking up information on mass ivermectin distribution is not that complex

The incorrect graphic has been shared 10,000s of times 🤷‍♂️

12/10 It is also worth briefly clarifying that this is only one method of ivermectin distribution - it does not include private prescription and uptake of ivermectin in any African countries during the pandemic, which is probably also a huge amount

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