Stop me if you’ve heard this one before: a cheap, widely-available drug is apparently a “global solution to the pandemic”. So went the stories in the Daily Mail, the Mirror, the Financial Times, and elsewhere last week, all focusing on the drug ivermectin. It’s been described as “a fundamentally potent cure” for Covid-19 by one of its main proponents, and the media articles reported that it might reduce coronavirus deaths by an incredible 75 per cent.
The story was picked up by media personalities who, shall we say, don’t follow the mainstream consensus view on Covid, such as Julia Hartley-Brewer and Maajid Nawaz (the latter of whom claimed that ivermectin “should render lockdowns redundant”). Indeed, claims about ivermectin almost always receive huge attention on social media, sometimes garnering many thousands of likes and shares. Dozens of times in the past couple of months, I’ve seen, or been sent, the link to a website that purports to show all the current studies on ivermectin along with a meta-analysis – a type of study where all the data are put together to see the overall effect.
Aside from it having a name that sounds like a town in the north of Scotland, what do we really know about ivermectin? Just like hydroxychloroquine, which is normally used to treat malaria but nevertheless became last year’s supposed “miracle drug” for Covid (and turned out to be useless), ivermectin is another drug repurposed from its original use. It’s normally an antiparasitic, routinely used to treat various kinds of worms, mites, and lice in humans and other animals. It also has a somewhat special aura, because its discoverers won the Nobel Prize in 2015.
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What about its use for Covid? Let’s take a look at the website from all the social media shares. The first line says that “100 per cent of the 42 studies to date show positive effects”. Impressive, right? Not necessarily. A 100 per cent positive set of studies might be consistent with a dramatic effect of the drug on death rates, but also with publication bias – where scientists are more likely to write up and publish results that show encouraging effects, and cover up those that show the drug in a bad light.
But even if there’s no publication bias, and the meta-analysis includes absolutely every study ever done on ivermectin and Covid, there’s a bigger problem: most of the studies are pretty shoddy. As noted in a careful review from Canada’s government drug review agency, and in another meta-analysis run by a group of international researchers that actually assessed study quality, the vast majority of the trials of ivermectin are low-quality (for example, most of them are very small, and in many of them the participants knew the treatment they were getting, going against the idea of a “double-blind” trial). They’re also poorly-reported – the scientific papers often didn’t contain enough information to find out what was actually done.
A meta-analysis is only as good as the studies that it’s meta-analysing; the “garbage-in, garbage-out” principle applies. For ivermectin and Covid, at the moment we mostly have garbage – and it wouldn’t be the first time that entire lines of low-quality medical research all pointed in the wrong direction. Now that at least one large, high-quality study of ivermectin and Covid is planned, we’ll soon have some better data. But at the moment the only scientific response is to withhold judgement.
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There’s a strange irony in watching the Covid-sceptics, who have been ultra-critical of any study that goes against their preconceived views, giving a free pass to reams of low-quality ivermectin research. But it raises the question: why would they want to seize on drugs such as ivermectin—as they previously did with the damp squib of hydroxychloroquine and the still-unproven effects of Vitamin D—and promote them to the high heavens? Why be so vehement about this, but be so dismissive of models, masks, tests, and sometimes even vaccines?
The reason for the double-standard is obvious: contrarianism. Treatments such as ivermectin (and hydroxychloroquine and Vitamin D) have never had mainstream approval, or the nod from UK or US medical regulators for their use against Covid. The contrarians can get excited about the apparently dramatic effects of ivermectin without having to agree with people they regard as wildly wrong on case rates, death rates, the effects of lockdowns and so on. They also get to feel the frisson of telling the world that they know better: they have secret knowledge about a super-important treatment, and the blinkered medical community just won’t listen.
But the ivermectin proponents have been duped – not by a specific person, necessarily, but by their own desire for a simple answer to the pandemic. It could easily be that, once the high-quality trial data comes in, we discover that ivermectin is useful under some circumstances. But there’s simply no basis for saying that at present. Until that evidence appears, the advocacy for ivermectin tells you more about the psychology of its proponents than it does about any effects of the drug.
[See also: International coronavirus vaccine tracker: how many people have been vaccinated?]
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