Convalescent plasma has been used to fight many infectious diseases, from scarlet fever in the 1930s to whooping cough and measles and, in more recent times, swine flu, Ebola, and Middle East respiratory syndrome.
The idea seems to make sense: The plasma of people who survive these diseases contains antibodies that may have helped them survive. When their plasma is donated and the antibodies are isolated from it and transfused, it could perhaps help newly infected people survive as well.
The problem is that no one is sure whether convalescent plasma works. In the face of a largely incurable disease like Ebola, some doctors, desperate to do something for a dying patient, try this approach without studying it. They engage in what I call “panic prescribing,” leaving the world with no idea if convalescent plasma does anyone any good or not.
President Trump has joined the panic prescription response to Covid. At a press conference on Sunday he said it was “proven to reduce mortality by 35 percent.” He said that even though the study being referred to did not have a control group. Even worse, 35% was an improvement in a select group of patients infected for fewer than three days. Few get any serious care that quickly. And worst of all, 35% refers to the improvement over survival given current supportive care efforts, which usually fail — not an absolute jump of 35% overall survival.
The president proudly made his announcement on the basis of weak data showing marginal improvement in a small segment of Covid-19 patients. He strong-armed scientists working in the federal government to open the floodgates for using convalescent plasma under an emergency use plan. This came only one week after scientists at the Food and Drug Administration and the National Institutes of Health had looked at the same evidence and declined to let doctors try convalescent plasma without getting better evidence that it does anyone good. The fact that it came a day before the start of the Republican National Convention tells a story all by itself.
Convalescent plasma appears to be fairly safe, but there are risks, as there always are with transfusions of blood products. No one who actually knows about the treatment is sure whether or why it works.
What Trump did not say, nor did officials from the FDA and the Department of Health and Human Services admit, is that no one knows how much plasma to give, who is a good donor, when is the best time in the disease course to transfuse convalescent plasma, how much, if any it actually improves survival, who are the best candidates for convalescent plasma, and whether it should be tried in combination with other therapies.
There are no careful peer-reviewed randomized trials of convalescent plasma for Covid-19 even though nearly 100,000 people in the U.S. have gotten it since March.
One group that knows how little we understand about convalescent plasma for Covid-19 is the Infectious Diseases Society of America. Here’s what its president, Dr. Thomas File, said in a statement (bolded emphasis his):
“While the data to date show some positive signals that convalescent plasma can be helpful in treating individuals with Covid-19, especially if given early in the trajectory of disease, we lack the randomized controlled trial data we need to better understand its utility in Covid-19 treatment. For this reason, IDSA supports the continued collection of data in randomized clinical trials to better understand the benefits of convalescent plasma treatment before authorizing its wider use in patients with Covid-19.”
In other words, President Trump has no basis for giving carte blanche for the use of convalescent plasma. Heads of the FDA and HHS, who do know better, got ordered to smile and nod in agreement with Trump’s convention surprise, lest they get tarred as deep state obstructionists. The rush should be trying to figure out if convalescent plasma really works, but the president has made that impossible since no trials will get funded or enrolled. Instead, the future holds vicious infighting as doctors struggle to grab some of the scarce supply of convalescent plasma for their patients, since the president has all but announced it as a cure.
The promotion of convalescent plasma shows once again that nothing but politics drives Trump’s response to the Covid-19 pandemic. He has made it clear that scientists who oppose him in the once highly respected FDA, CDC, and NIH will have no standing if they deviate from his agenda. And he has signaled that he will not hesitate to promote a vaccine as ready to go — data be damned — if he needs an October surprise to salvage his political future.
Despite Trump’s decision to promote it, we will be no closer to knowing if it works, for whom, and how best to use it — knowledge that should have preceded any emergency use authorization for convalescent plasma. Once emergency use is permitted, the ability to do clinical trials to answer these questions is put in extreme jeopardy.
Convalescent plasma will now rapidly become the treatment of choice for those rich enough, connected enough, and lucky enough to access it. It is in very short supply. So doctors, besieged by patients and families to use it on their loved ones based on the publicity, will resort to panic prescribing. Who will get this scarce resource? Emergency use is usually not covered by third-party payers. So, the rich will likely be first in line.
Panic is not the way to identify treatments for Covid-19. President Trump’s disdain for science and medicine in favor of politics is not likely to matter much to improving the fate of the victims of Covid-19.
Arthur Caplan is professor of bioethics and the founding head of New York University School of Medicine’s Division of Medical Ethics.