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Could Drug for Parasites Also Fight Coronavirus?

Ivermectin is a drug for parasites. It saved the sight of millions in Africa. It protects dogs against heartworm. Does it work against COVID?
Could Drug for Parasites Also Fight Coronavirus?
Hiking woman with rucksack and her bernese mountain dog on a trail

We started writing about the drug IVERMECTIN against COVID-19 back in April, 2020. That’s because Australian researchers reported that this drug for parasites had strong antiviral activity vs. the coronavirus. That was test tube research (Antiviral Research, April 3, 2020). More than a year has passed, and like nearly everything else associated with the pandemic, views on ivermectin became polarized. The time has come for an update and some inside information.

A Drug For Parasites Vs. COVID-19?

Some advocates were in favor of using ivermectin immediately and widely to treat people with COVID-19. Others, possibly more skeptical, wanted to hold out for well-conducted clinical studies. But randomized controlled trials require time to be done properly. In a race against the SARS-CoV-2 virus it wasn’t clear we’d have that time.

Now, however, the scientific reports are starting to appear. A group of British scientists have published a systematic review and meta-analysis of ivermectin for preventing and treating COVID-19 (American Journal of Therapeutics, online June 17, 2021). They examined 15 trials and found that people given ivermectin were less likely to die from COVID-19 than those who did not take the drug. Ivermectin also appeared to prevent infection with the coronavirus, but that evidence is far weaker.

The researchers concluded:

“The apparent safety and low cost suggest that ivermectin is likely to have a significant impact on the SARS-CoV-2 pandemic globally.”

Another review in the same journal was conducted by investigators who have been unabashed cheerleaders for the drug. They reviewed 18 randomized controlled trials of ivermectin and concluded that it is effective in all phases of COVID-19 (American Journal of Therapeutics, May-June 2021).

Where Did This Amazing Drug For Parasites Come From?

Fifty years ago a Japanese microbiologist tested some dirt from a golf course near Honshu. He and his colleague William Campbell at Merck discovered that unique bacteria in that soil had anti-parasitic activity against roundworms in mice. Their research led to a Nobel Prize in Physiology or Medicine in 2015. 

Merck introduced ivermectin for treating parasites in animals in 1981. Many dog lovers still administer a monthly dose of ivermectin (Heartgard) to their canine companions to prevent heartworm.

Then the company discovered that ivermectin could also fight off the parasite Onchocerca volvulus that causes “river blindness” in humans. Infected Simulium black flies carry the larvae of this worm. It causes untold misery in Africa and Latin America.

Symptoms include skin rashes, nodules and horrific itching. Inflammation in the eye can lead to clouding of the cornea, optic nerve damage and ultimately blindness. Ivermectin was approved to treat people with river blindness in 1987. The brand name was Mectizan. It has saved the sight of millions of people in Africa and Latin America. Some experts consider it a wonder drug on a par with aspirin and penicillin.

It has since been found to work against a range of parasites. Although most of these are in the form of filaria, tiny thread-like worms, it is also effective  against lice and scabies.

A review in the Journal of Drugs in Dermatology (March, 2016) states:

“Numerous studies report low rates of adverse events, as an oral treatment for parasitic infections, scabies and head lice. Ivermectin has been used off-label to treat diseases associated with Demodex mites, such as blepharitis and demodicidosis. New evidence has linked Demodex mites to rosacea, a chronic inflammatory disease. Ivermectin has recently received FDA and EU approval for the treatment of adult patients with inflammatory lesions of rosacea, a disease in which this agent has been shown to be well tolerated.”

None of this got anyone particularly excited. But then COVID-19 hit.

Ivermectin and the Coronavirus:

There have been dozens of publications about ivermectin vs. COVID-19. There are enthusiasts and critics. Like just about everything related to this virus, there are strong emotions. We don’t understand why this amazing drug has been caught in the crossfire, but it has. 

A Drug for Parasites Has Antiviral Activity:

It may seem surprising that a drug for parasites would knock out viruses. However, scientists have previously found that it can slow proliferation of the virus that causes dengue fever.

Australian researchers have found that ivermectin has strong antiviral activity (Antiviral Research, online, April 3, 2020):

“Taken together these results demonstrate that ivermectin has antiviral action against the SARS-CoV-2 clinical isolate in vitro, with a single dose able to control viral replication within 24–48 h in our system…Ultimately, development of an effective anti-viral for SARS-CoV-2, if given to patients early in infection, could help to limit the viral load, prevent severe disease progression and limit person-person transmission…This Brief Report raises the possibility that ivermectin could be a useful antiviral to limit SARS-CoV-2, in similar fashion to those already reported…”

A Randomized Control Trial of a Drug for Parasites:

More than a year ago we wrote:

“Unfortunately, this basic laboratory research is still far from uncovering clinical efficacy. Since ivermectin has been used in human medicine for decades, clinicians already know quite a bit about its side effects. However, as with most of the other drugs currently under study, we won’t know if it works against COVID-19 until clinical trials are conducted.”

Now, we have clinical research to support ivermectin against COVID-19 (EClinicalMedicine, Jan. 19, 2021). Researchers treated 24 COVID patients in Pamplona, Spain. Half were randomized to receive ivermectin. The others got placebo.

Patients who received ivermectin had substantially less viral load after four days. Seven days after treatment with the drug, the viral load was 18 times lower than in the placebo patients. The treated patients were half as likely to lose their sense of taste and smell and a third less likely to develop a cough.

More Data on Ivermectin to Fight COVID Infections:

Larger clinical trials have followed. The reviewers writing in the American Journal of Therapeutics are cautiously optimistic. 

They introduced their paper explaining why they think ivermectin offers promise against COVID:

“Developing new medications can take years; therefore, identifying existing drugs that can be repurposed against COVID-19 that already have an established safety profile through decades of use could play a critical role in suppressing or even ending the SARS-CoV-2 pandemic. Using repurposed medications may be especially important because it could take months, possibly years, for much of the world’s population to get vaccinated, particularly among LMIC populations.

“Currently, ivermectin is commercially available and affordable in many countries globally.”

Some physicians may have been surprised that this drug for parasites performed so well against COVID.

Here are the results of the review:

“Meta-analysis of 15 trials, assessing 2438 participants, found that ivermectin reduced the risk of death by an average of 62% (95% CI 27%–81%) compared with no ivermectin treatment [average RR (aRR) 0.38, 95% CI 0.19 to 0.73; I2 5 49%]; risk of death 2.3% versus 7.8% among hospitalized patients in this analysis, respectively.”

Their conclusion is quite upbeat:

“Overall, the evidence also suggests that early use of ivermectin may reduce morbidity and mortality from COVID-19.”

Perhaps that is why the NIH Treatment Guidelines Panel has upgraded its ivermectin recommendation. Instead of warning against its use, as the panel did previously, they have changed to neither for nor against. As a result, ivermectin is in the same category as monoclonal antibodies. As more research becomes available, clinicians will be better able to gauge the effectiveness of ivermectin against COVID-19.

Most public health officials have remained cautious about recommending ivermectin as an anti-COVID medication. They call for larger and more extensive randomized controlled trials.

Some states in India and a few European countries such as Slovakia are permitting its use. The authors of the most recent meta-analysis suggest that:

Ivermectin is likely to be an equitable, acceptable, and feasible global intervention against COVID-19.”

A word of caution:

No one should EVER take veterinary medicine! We will need confirmatory research with dosage guidelines before doctors will prescribe ivermectin for COVID-19. We just hope that this extraordinary medicine soon gets the credit it deserves. With COVID cases now on the increase, we need all the tools we can muster.

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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.” .
  • Caly L et al, "The FDA-approved drug ivermectin inhibits the replication of SARS-CoV-2 in vitro." Antiviral Research, April 3, 2020. DOI: 10.1016/j.antiviral.2020.104787
  • Chaccour, C., et al, " The effect of early treatment with ivermectin on viral load, symptoms and humoral response in patients with non-severe COVID-19: A pilot, double-blind, placebo-controlled, randomized clinical trial," EClinicalMedicine, Jan. 19, 2021, DOI:https://doi.org/10.1016/j.eclinm.2020.100720
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