Last week, I told you about a British study that showed a cheap steroid called dexamethasone reduced deaths by a third in hospitalized Covid-19 patients.

In the days since that study was released, hospitals across the United States saw a surge in demand for the drug, leading to a shortage of several injectable versions.

Hospital orders for dexamethasone surged 183% on June 16, when the University of Oxford researchers released their data that suggested dexamethasone could improve the odds of survival in the sickest patients.

At least three manufacturers reported shortages as of Wednesday, according to the American Society of Health-System Pharmacists.

The World Health Organization has called for a rapid increase in production of dexamethasone.

It’s important to point out that the authors of that study showed that the steroid helped seriously ill COVID-19 patients on ventilators or on oxygen. It didn’t help people with less severe symptoms.

That’s why the WHO stresses that dexamethasone should only be used for patients with severe or critical disease under close clinical supervision. There is no evidence that the drug works for patients with mild disease or as a preventative measure.