When vaccine-sceptic Americans began ingesting an anti-worm paste designed for farm animals in an attempt to ward off Covid-19, regulators issued a sharp rebuke.
“You are not a horse. You are not a cow. Seriously, y’all. Stop it,” the Food and Drug Administration (FDA) posted on social media at the time.
Four years later, the drug ivermectin is again being widely touted on social media, once more without hard evidence, as a cure for a different deadly disease: cancer.
Google searches for “ivermectin” rose to their highest level since the pandemic in January, days after the actor Mel Gibson joined The Joe Rogan Experience podcast to espouse the merits of the drug. The Oscar-winning actor and director claimed that a cocktail of ivermectin and other drugs had cured several friends of stage 4 cancer.
“This stuff works, man,” he enthused. The episode has more than ten million views on YouTube alone. Conservative politicians have latched on to ivermectin as a new front line in the culture wars, a symbol of free speech and medical freedom, and Republican-dominated states are seeking to authorise over-the-counter sale of the drug.
In North Carolina, a bill to allow non-prescription use of ivermectin was passed in the state’s house of representatives on Wednesday. Last month Brad Little, the Republican governor of Idaho, signed a bill that would make his state follow Arkansas and Tennessee in allowing chemists to sell the drug over the counter.
Dan Zuckerman, an oncologist at St Luke’s Cancer Institute in Boise, Idaho’s state capital, has seen a sharp rise in the number of patients asking about the merits of the deworming paste as a cancer cure. “It’s all the time, it’s every day and easily more than 50 per cent of patients ask,” he said. “It’s always in the last minute of the visit, and they’re like, ‘I just want to run one more thing by you.’ And, you know, that’s the question. My nurse rolls her eyes. We’re all used to it.”
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Many doctors are alarmed. They have reported seeing patients with early, treatable cancer choosing ivermectin over traditional care such as chemotherapy, only to return months later when tumours have spread to their bones and brain.
“I just say, ‘Look, the data behind it is very poor and it’s not considered standard for a reason … There are some health risks,’” Zuckerman said. “Most of us are just quietly resigned. Patients are going to do what they’re going to do.”
He is frustrated by the explosion of misinformation online that deceives his patients. “People always say, ‘I do my own research,’” Zuckerman added. “Privately, I find that so irritating and, frankly, stupid. But I would never say that to a patient because people are fighting for their lives.”
Misinformation surrounding the anti-parasitic drug grew during the pandemic. Ivermectin and the antimalarial drug hydroxychloroquine were widely recommended as cures for Covid on Facebook groups and Reddit communities used by supporters of the anti-vaccine movement.
At the time, US hospitals reported a spike in patients who had been poisoned after taking veterinary-grade ivermectin intended for livestock. Two deaths in New Mexico were linked to the drug. The FDA has warned that high doses of ivermectin can cause seizures, coma and death.
Robert F Kennedy Jr, President Trump’s health secretary, has in the past supported using the drug to treat Covid. Steven Hatfill, a virologist who worked for the first Trump administration and promoted hydroxychloroquine as a treatment for Covid, is said to be in line for a senior pandemic prevention role at the health and human services department.
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While the threat of Covid has faded, ivermectin’s cult following has grown and evolved. False online reports that cancer is a parasite have spurred renewed interest in ivermectin and fenbendazole, another drug used to deworm dogs.
Ivermectin has some legitimate medical uses in humans. Two scientists who studied the drug won the Nobel prize for medicine in 2015 for research into how the drug can be used as an effective treatment for river blindness caused by roundworm parasites in sub-Saharan Africa.
The accolade, however, is widely cited among conservative influencers and online communities to support baseless claims for ivermectin’s powers. They include Joe Grinsteiner, 54, a country singer and farmer in rural Michigan. Grinsteiner’s videos became widely shared on social media earlier this year when he posted a video on Facebook claiming that ivermectin cured his wife’s cervical cancer and his skin cancer.
He now has almost half a million followers on Facebook. In one video on his website, he smears the paste on his tongue. “It tastes like shit,” he admitted to The Times. “But my energy level has improved. I have better skin colour. My mental clarity came back.”
Grinsteiner gave ivermectin to his animals for years before the pandemic. Wary of the Covid vaccine, he and his wife began taking it themselves.
Grinsteiner, who is a Trump supporter, denies that ivermectin is a “right-wing thing”, adding: “The media has tried to make it look like we’re kind of crazy, but when your doctor says, ‘There’s nothing more we can do’, there’s no such thing as left and right.”
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Doctors and influencers may agree on one thing: new state laws making it easier to buy ivermectin may make little difference. Cheap, veterinary-grade ivermectin is already freely available at farm stores across the US and online. A single tube of apple-flavoured ivermectin, which has a horse on the box, costs $3.99 from Walmart and can also be bought on Amazon. A tube of lotion for head lice containing a mild dose of ivermectin, by contrast, sells on Walmart’s website for $28.52.
At a Tractor Supply store in Boise last week, staff said they were sold out of the apple-flavoured brand. One staff member admitted that there was “no way to know” whether customers were buying the paste for their animals or themselves. “We sell it for horses,” he said.
