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Ivermectin for COVID? Unproven treatment stokes concern in Japan

  • December 21, 2021
  • , The Japan Times
  • English Press



Authorities have flagged concerns over scores of messages posted on websites for agents that import drugs into Japan from those who have mail ordered the anti-parasite drug ivermectin.


“I just received the package and, to prevent (coronavirus) infection, I’m going to take it from today,” a 52-year-old man wrote in a message posted in September.


Ivermectin is touted by some people opposed to COVID-19 vaccinations as a “miracle drug” for the disease, despite a lack of overwhelming scientific evidence supporting it. But it is perhaps the one drug over which scientists around the world are most divided in terms of its efficacy in preventing COVID-19 and treating the illness.


The drug, used globally to treat parasitic worms and skin conditions, has not been officially approved for use to treat COVID-19 in Japan, the U.S. or most countries in Europe. The health ministry says the drug should be used only in clinical trials in Japan. The use of potentially unsafe imported medications, which may be counterfeit or adulterated, is not subject to compensation provided by Japan’s drug regulator should any serious health problems arise.


But that has not dissuaded some unvaccinated people from seeking out the drug in case they are infected with the coronavirus, as the internet abounds with misleading claims touting the drug’s efficacy in treating COVID-19. An article on the website of right-wing U.S. radio host Hal Turner even erroneously claimed in October that Japan successfully ended the pandemic in the country in less than a month after it dropped its vaccine rollout and relied on ivermectin instead for treatment.


Amid a lack of convincing clinical data in Japan, Kitasato University Hospital worked on a doctor-led midstage clinical trial, the results of which are not yet available. Kowa Co. has recently launched a final-phase clinical trial.


The Tokyo Medical Association has also extended its support to Kowa’s trial. At the height of Japan’s fifth wave in mid-August, its president, Haruo Ozaki, proposed the emergency use of ivermectin to deal effectively with the pandemic.


“Although an examination is necessary by conducting a clinical trial properly, under a strained situation like this, I think we’ve reached a stage where it’s OK to have the authorization issued to use ivermectin on patients after getting their informed consent,” he told reporters on Aug. 13.


To ascertain its efficacy, the U.K.’s Platform Randomized Trial of Treatments in the Community for Epidemic and Pandemic Illnesses, the world’s largest clinical trial of possible COVID-19 treatments for recovery at home and other nonhospital settings, started investigating ivermectin’s use in adults 18 years old and above in June, but the trial is currently paused due to temporary supply issues.


With known antiviral properties, ivermectin has been shown to reduce the replication of the coronavirus in laboratory studies, the University of Oxford says. But although the drug has been used routinely to treat COVID-19 in some countries, such as Slovakia and Greece, there is little evidence from large-scale randomized controlled trials to demonstrate that it can speed up recovery from the illness or reduce hospital admission, it added.


Merck & Co.’s patent on ivermectin has expired, and cheap, generic versions are already widely available across the world, which is one reason why some doctors have turned to it for treating COVID-19 since early in the pandemic.


But Dr. Masahiko Okada, professor emeritus of Niigata University, says the vast majority of studies on ivermectin have not been peer reviewed and that the data from many clinical trials has not been made public, raising questions about its efficacy in treating COVID-19. He added that those studies may prompt some people in Japan to mistakenly believe that it can prevent the disease or at least serious symptoms.


A study published in the journal Nature Medicine has also pointed out flaws in several studies that claim ivermectin is clinically beneficial.

“A normal citizen wrote me an email saying that he drinks ivermectin every day and feels fine,” he said. “That scares me. The scientific consensus of the medical industry in developed countries is against ivermectin for treating COVID-19, though Japan has not reached its conclusion.”


Satoshi Omura, distinguished emeritus professor at Kitasato University, shared the Nobel Prize in physiology or medicine in 2015 for the discoveries that led to ivermectin, which revolutionized the treatment of some of the most devastating parasitic diseases that affect the world’s poorest. The medication has been approved for use in animals for prevention of heartworm disease and for use in humans to treat infections caused by parasites.


In the U.S., some people have even resorted to taking ivermectin prepared for animals to prevent and cure COVID-19, but the U.S. Food and Drug Administration says that taking the animal version — which is very different from that approved for humans — is “dangerous” and that taking large amounts can lead to nausea, seizures, coma and even death. Merck, one of the drug’s manufacturers, has said that it does not believe the available data supports the safety and efficacy of ivermectin for treating COVID-19.


The World Health Organization says the evidence on the drug’s use to treat COVID-19 patients is “inconclusive” and recommends that it only be used within clinical trials.


Cochrane Library, a trusted source of independent databases to inform health care decision-making, has concluded that completed studies on ivermectin are small and that few are considered high quality.


“Overall, the reliable evidence available does not support the use of ivermectin for treatment or prevention of COVID-19 outside of well-designed randomized trials,” it said.


Despite the ongoing studies into ivermectin’s efficacy, it remains to be seen whether it can retain interest in the face of oral antiviral drugs developed specifically for treating COVID-19.


A health ministry panel is set to meet Friday to decide whether to approve Merck’s molnupiravir for the treatment of mild and moderate COVID-19 symptoms. Other drugs are following close behind in the race to develop oral treatments that can be taken at home, including those developed by Pfizer Inc. and Shionogi & Co.

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