On Monday night, Dr. Stephen Hahn, the commissioner of the Food and Drug Administration, addressed inaccurate and misleading remarks he made in a news conference the previous evening. Dr. Hahn had initially claimed that plasma from recovered Covid-19 patients — what’s known as convalescent plasma — could save 35 out of every 100 people who contract the disease.
As he has since explained on television and Twitter, his initial assessment conflated two different things: relative risk reduction (that is, how much a treatment reduces the risk of death in one group of patients compared to a different group) and absolute risk reduction (that is, how much a treatment reduces the risk of death in a group of patients compared to the rest of the population who didn’t get the treatment).
To proponents of convalescent plasma therapy, this might seem like an inconsequential flub: Why split hairs if lives were saved? But the survival benefit Dr. Hahn initially mentioned applies only to a narrow subset of patients: Those younger than 80 years old who were hospitalized but not on ventilators and who received plasma with high levels of antibodies within three days of diagnosis were 35 percent less likely to die than those who received plasma with low levels of antibodies.
If the former group of patients were compared instead to the wider population, the benefit would shrink considerably. (The data in question also has several other serious limitations, which the commissioner did not acknowledge or address.)
Dr. Hahn knows this — or at least he ought to. As an oncologist by training and a former hospital executive, he should be familiar with basic statistics. The trouble is, Dr. Hahn is serving a president who routinely demonstrates an overt hostility to science and who is facing a tough re-election. And he’s being pressed by that president to clear drugs and vaccines for use as quickly as possible — even if they may not have been proven safe and may not be effective.
Convalescent plasma is not an unreasonable thing for doctors and scientists to pin their hopes on — it has proved effective for other diseases, and so far it does appear to be safe for Covid-19 patients. But it has not yet shown any real benefit for them, and it’s the job of officials like Dr. Hahn to be as clear as possible about that. There is a playbook for communicating information during a public health crisis — it calls for honestly about what isn’t known and transparency about how decisions are being made in light of that uncertainty.
Dr. Hahn could have stood by leaders from the National Institutes of Health who advised hitting pause on the use of convalescent plasma until more data was available. Or he could have defended F.D.A. scientists who advised moving forward even though data was limited. Instead, he followed his boss’s lead, propping up victorious statements with fuzzy numbers. That’s perhaps unsurprising: In a world where disinfectant therapy is discussed with a straight face, the difference between relative and absolute may indeed seem small.
But even small compromises with the truth can have big consequences for public trust, and for the course of global pandemics. It’s worrisome that a doctor in charge of one of the nation’s top regulatory agencies — who will play a leading role in the coming decisions about which vaccines are safe and effective enough to be injected into Americans’ bodies — doesn’t seem to realize that.