The requests were strange: Customers flocking to a Nevada feed store were asking for an animal deworming drug that they said worked for covid-19.

But elsewhere, interest in ivermectin is running high, despite insufficient evidence that it works as a treatment for covid-19 and the sometimes dangerous consequences when people take the animal version.

The Food and Drug Administration said at least three people were hospitalized in February after taking the veterinary formulation.

Kory, a co-founder of the Front Line Covid-19 Critical Care Alliance, a group of physicians and scientists from several countries, argues that studies from around the world show ivermectin is a “miracle drug” for covid-19 and should be deployed immediately.

A British trial called Recovery has provided important information about older drugs, finding that hydroxychloroquine did not help hospitalized covid-19 patients, while the steroid dexamethasone could be a lifesaver.

Interest in ivermectin for covid-19 surged last spring after a small Australian study found that the drug inhibited the replication of the coronavirus in laboratory tests.

Scientists warn, however, that such anecdotes do not prove a treatment works, because most people who get covid-19 eventually recover.

Last fall, it began focusing on ivermectin as several studies emerged from countries in Southeast Asia and South America suggesting that it could be beneficial in treating covid-19.

Kory said he now works as a “locum tenens” physician — a doctor who works in temporary jobs — and as president and chief medical officer of the Front Line Covid-19 Critical Care Alliance.

Last August, the NIH committee that issues covid-19 treatment guidelines recommended against the use of ivermectin outside of clinical trials.

But after a presentation by Kory and his colleagues in January, the panel adopted a neutral stance, saying there was “insufficient data to recommend either for or against the use of ivermectin for the treatment of covid-19.” It said some studies showed benefits and others did not.

Several weeks later, the lnfectious Diseases Society of America, made up of infectious-disease physicians, said most of the ivermectin studies were too small, weren’t properly randomized or had other flaws, and said the drug should not be used outside of trials.

Adarsh Bhimraj, an infectious-disease doctor at the Cleveland Clinic and a member of the treatment-guidelines panel, pointed to what he described as a well-designed, randomized, placebo-controlled trial in Colombia that found the drug did not help patients with mild covid-19.

Hydroxychloroquine not effective for early treatment of mild covid-19