Ivermectin & COVID-19: Let's keep a One Health perspective.

Despite uncertainty about its clinical benefit, ivermectin has been used for COVID 19, even in prophylaxis. The European Medicines Agency (EMA) has advised against its use for the prevention or treatment of COVID-19 outside randomised clinical trials. Although the potential negative environmental effects of ivermectin have been widely recognised when used in veterinary medicine, scarce attention has been devoted to the potential ecotoxicological impact of human use. We believe is time to include One Health's philosophy in our daily practice. In the specific case of ivermectin & COVID 19, environmental aspects should also be on the table.

A plethora of different drugs with antiviral activity have been tested for the treatment of COVID-19. Despite uncertainty about its clinical benefit, ivermectin has been widely used in different stages of the disease, even in prophylaxis (Behera et al., 2021). Very recently, the European Medicines Agency (EMA) has advised against its use for the prevention or treatment of COVID-19 outside randomised clinical trials (European Medicines Agency, 2021).

The discovery of ivermectin revolutionized the treatment of some of the most devastating parasitic diseases, like onchocerciasis and lymphatic filariasis, to such a point that Omura & Dr Campbell, discoverers of the drug, received the Nobel Prize in Physiology or Medicine in 2015 for their invaluable contribution (The Nobel Prize in Physio, 2015). Apart from its use in mass drug administration programs in humans, ivermectin has also been extensively used in veterinary medicine to treat and prevent parasitic worm diseases in livestock.

A proportion of administered ivermectin is excreted unaltered mainly with faeces, ending up in soil and other environmental matrices. Far from being selective, this drug also affects many non-target organisms, such as insects. In fact, available risk assessments confirm extremely high toxicity for invertebrates. Moreover, significant retention in the wastewater treatment plant sludge is also expected, so in the case of sludge reclamation as soil fertilizer in agricultural soils a cautious approach should be mandatory (Tarazona et al., 2021). Although the potential negative environmental effects of ivermectin have been widely recognised when used in veterinary medicine, scant attention has been devoted to the potential ecotoxicological impact of mass drug administration programs in humans so far (Orive and Lertxundi, 2020). In fact, as far as we are aware, ivermectin has never been measured in any wastewater influent or effluent.

We believe is time to include One Health's philosophy in our daily practice. We can no longer neglect the interconnection between people, animals, plants, and their shared environment. In the specific case of ivermectin & COVID 19, these environmental aspects should also be on the table.

Funding information

The research received no funding.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.