Here’s another questionable COVID cure
Better drugs to treat COVID-19 look more attractive than ever. Hopes that vaccines would roll back the virus with herd immunity are fading as the more transmissible delta variant sweeps the world, cases rise and millions of people hesitant to vaccinate settle in.
Beyond that, it is disturbing to learn of even the extremely rare cases where young and healthy people suffer and die from diseases potentially linked to vaccines: blood clots, inflammation of the heart and, more recently, the crippling disease known as the name of Guillain-Barre syndrome.
Such rare but terrible results would seem more tolerable in a drug that cures the sick, and now that clinical studies have dampened the enthusiasm for hydroxychloroquine, touted at the start of the pandemic by President Donald Trump, some scientists are reporting studies promising an antiparasitic drug called Ivermectin. Both drugs were particularly attractive because they had already passed safety tests and were being used to fight other human diseases.
And, last week, it seemed like welcome good news had come from a review article concluding that ivermectin can prevent serious illness and save lives.
This study attracts the attention of the libertarian and conservative media. The emphasis on treating the sick draws more on the ethics of personal responsibility embraced by conservatives, while those on the left are more comfortable with the collectivist ethic of accepting the small risk and the discomfort associated with vaccines for the good of society.
But there is a problem. Experts disagree on the conclusions to be drawn from clinical studies with ivermectin, and the laboratory experiments that propelled the drug into trials suggest in the first place that it only fights the virus effectively at low levels. doses likely to be toxic.
As with hydroxychloroquine, the high hopes for ivermectin owe more to politics than science.
Effective treatments for viral diseases are even rarer than effective vaccines, according to medical chemist Derek Lowe, who has worked for several pharmaceutical companies and writes a drug development blog for Science Magazine called “In the Pipeline.”
A recently discovered cure for hepatitis C is a rare exception, as is the cocktail of drugs that prevent HIV infections from turning into AIDS. There are medicines that can control but not cure herpes. And that’s the breadth of Lowe’s list of highly effective antiviral drugs.
Most drugs that kill a foreign invader are also likely to be somewhat toxic – so it’s hard to find mechanisms that destroy them and spare us. Parasites and bacteria are generally easier to kill than viruses, Lowe said, because larger pathogens have more active parts that might be more vulnerable to chemical disturbances than human cells.
Vaccines, on the other hand, tend to prevent viral diseases with fewer side effects because they don’t work out of toxicity but by boosting the immune system. And the immune system of animals has had hundreds of thousands of years to successfully kill the invaders.
Ivermectin was chosen for clinical testing for legitimate reasons. It is true, as some detractors have said, that it is used as a deworming medicine for sheep and other farm animals. But it is also one of the few miracle drugs for humans, having saved hundreds of thousands of people from blindness due to onchocerciasis, also known as river blindness, or suffering from elephantiasis. , a disease of the swelling of the limbs. The drug’s discoverers won a Nobel Prize in 2015.
One of the co-inventors, William Campbell, then at Merck & Co., developed a new technique for screening a large number of compounds to find those that could kill the parasites – ultimately leading to a positive signal of a compound isolated from soil bacteria found near a golf course in Japan.
Large-scale screening techniques allowed scientists to discover that the drug also fights SARS-CoV-2, the virus that causes COVID-19. It’s always worth starting with a drug that’s already in use, Lowe said, because the safety data has already been gathered.
Ivermectin does not kill parasites; it cures parasitic diseases by disrupting the reproduction of the parasites. “In the treatment of parasites, one of the things that makes ivermectin so wonderful is that it can be given in extremely low doses, so it’s very safe and well tolerated,” Lowe said.
This does not appear to be the case in virus test tube studies. There, the drug seems to work only at a dose high enough to trigger a mechanism called phospholipidosis – a process Lowe likens to killing things with detergent. This prevents viruses from entering cells, but it is also extremely toxic to humans.
So what would explain the positive findings of the new meta-analysis, published in the American Journal of Therapeutics? In the many clinical studies analyzed, it was given in doses low enough not to kill people. Lowe said he was skeptical because the strongest and best-conducted studies showed nothing and only the weakest seemed to show an effect. Ivermectin owner Merck delivered a skeptical assessment of its usefulness against COVID-19 similar to Lowe’s.
Several larger and more definitive trials are underway, so there is still a chance that it will work. And it’s worth it, as long as people don’t put too much hope in it.
Anecdotes about the miracles of COVID ivermectin abound for the same reason people believe in cold remedies: Most people get better on their own and then attribute their recovery to medication. Even with the much more dangerous COVID-19, people tend to overestimate their chances of dying and imagine that whatever they took must be responsible for their recovery. But what really saved them was the human immune system – which in most cases works and, with more widespread vaccination, will work even better.