https://twitter.com/JohnBasham/status/1474948368132624386?s=20
The mechanisms of action of ivermectin against SARS-CoV-2—an extensive review
21 December 2021
Considering the urgency of the ongoing COVID-19 pandemic, detection of new mutant strains and potential re-emergence of novel coronaviruses, repurposing of drugs such as ivermectin could be worthy of attention. This review article aims to discuss the probable mechanisms of action of ivermectin against SARS-CoV-2 by summarizing the available literature over the years. A schematic of the key cellular and biomolecular interactions between ivermectin, host cell, and SARS-CoV-2 in COVID-19 pathogenesis and prevention of complications has been proposed.
Introduction
A relatively recent surge in zoonotic diseases has been noted over the past few decades. Several reasons could be responsible for this “spill-over” of disease-causing agents from animals to humans. These include an exponential rise in the global population causing man to encroach new ecological habitats in search of space, food, and resources as well as improved opportunities for rampant wildlife trade causing interspecies pathogen jumps. The 1980s was known for HIV/AIDS crisis that originated from the great apes, while the avian flu pandemic in 2004–07 came from the birds. The pigs led to the swine flu pandemic in 2009 and bats were the original hosts of Ebola, severe acute respiratory syndrome (SARS), Middle Eastern respiratory syndrome, and probably SARS coronavirus 2 (SARS-CoV-2) outbreak as well.
COVID-19 has already caused millions of deaths worldwide and has paralyzed not only the world’s healthcare system but also the political and economic relations between countries [1]. The fact that the SARS-CoV-2 virus has been thought to have originated from wildlife and may have “jumped” into humans, not only highlights future risks from animal-borne diseases but also provides an important clue to its resolution. In such a scenario, where this “jump” has been made from animal to human, it seems only logical to review a drug that has worked efficiently against a disease-causing agent and is available in a form that is safe for human consumption since the early 1980s.
Ivermectin belongs to a group of avermectins, which is a group of 16 membered macrocyclic lactone compounds discovered at the Japanese Kitasato Institute in 1967 during actinomycetes cultures with Streptomyces avermitilis [2]. This drug radically lowered the incidence of river blindness and lymphatic filariasis and was discovered and developed by William C. Campbell and Satoshi Ōmura for which they received the Nobel Prize in Physiology or Medicine in 2015 [3, 4]. Ivermectin is enlisted in the World Health Organization’s Model List of Essential Medicines [5].
Drug repurposing, drug redirecting, or drug reprofiling is defined as the identification of novel uses for existing drugs. The development risks, costs as well as safety-related failure, are reduced with this approach since these drugs have a well-established formulation development, in vitro and in vivo screening, as well as pharmacokinetic and pharmacodynamic profiles. Moreover, the first clinical trial phases of many such drugs have been completed and can be bypassed to reduce several years of development. Therefore, drug repurposing has the potential to reduce the time frame for the whole process by up to 3–12 years and carries great potential [6].
Although several drugs received emergency use authorization for COVID-19 treatment with unsatisfactory supportive data, ivermectin, on the other hand, has been sidelined. Nevertheless, many countries adopted ivermectin as one of the first-line treatment options for COVID-19.
With the ongoing vaccine roll-out programs in full swing across the globe, the longevity of the immunity offered by these vaccines or their role in offering protection against new mutant strains is still a matter of debate. Thus, the search for new, effective antivirals continues.
Several doctor-initiated clinical trial protocols that aimed to evaluate outcomes, such as reduction in mortality figures, shortened length of intensive care unit stay and/or hospital stay, and elimination of the virus with ivermectin use have been registered at the US ClinicalTrials.gov [7]. Controlled clinical trials using ivermectin are underway, including one being conducted by the National Institutes of Health (ACTIV-6) [ClinicalTrials.gov Identifier: NCT04885530] in the USA and a second in the UK (PRINCIPLE) [ISRCTN registry: ISRCTN86534580] [8, 9]…,more
https://www.nature.com/articles/s41429-021-00491-6