Clinical trials of various Covid-19 treatments are, of course, ongoing — and the FDA has ramped up its capacity to approve new studies. But researchers are grappling with an overarching concern that with so much off-label, ad hoc, and informal experimentation underway in the battle to contain the pandemic, the baseline conditions needed for decisive studies of Covid-19 interventions are becoming more challenging to achieve. They also worry that if the public comes to believe that the evidence on hydroxychloroquine is settled, few patients will want to participate in clinical trials at all. They’ll just want the hydroxychloroquine — and there is already evidence that this is happening.

Alvarez says he gets it. “If the [French] study can be interpreted in a good light and it’s the only one that can, then individual physicians all around the world are hanging onto that because we want to help,” he said. “We’re scared of what we’re seeing. I think any physician would tell you that this is scary and we’re grasping at straws to help people.”

And yet, he and other scientists say, all that grasping might actually be inhibiting the country’s ability to figure out the most effective ways to treat Covid-19.