As a scientist, I know that one of the keys to emerging from the current COVID-19 pandemic is a safe and effective vaccine. Over 100 vaccine candidates are being considered and some will soon advance to large human trials. Thousands of people will receive the vaccines. Researchers will see if their infection rate is any different from unvaccinated people’s and verify the vaccine’s safety.
Because, even in the absence of a vaccine, during a span of several months only a small fraction of any population becomes infected, it will require a large number of people and/or a long time to determine whether a given vaccine provides any protection. Meanwhile, hundreds of millions of people in the United States and billions of people worldwide are unprotected, and many will become infected. Some will die, and the longer it takes to determine which are the good vaccines, the more people will die.
There is an alternative — challenge trials. In such trials, a smaller group receives a vaccine and is then deliberately exposed to the virus with a standardized dose. The advantage of such trials is that one does not wait for “natural” infection to happen by chance. Nor does one have the variability of natural infection, from a brief encounter with an asymptomatic individual to a lengthy encounter with a “super spreader.” The disadvantage is that some of the volunteers for such a study are likely to die.
Is this proper? Is it ethical?
I volunteer myself
The ethical status of challenge trials is problematic because COVID-19 can be fatal, with no known effective therapy. Some traditional rules for human subject studies preclude challenge trials in this case.
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Various specific ethical arguments against challenge trials arise. Some contend that infecting subjects violates the Hippocratic oath, often expressed as, “First, do no harm," and conjures up memories of clearly unethical studies like Tuskegee. Others argue that if a candidate coronavirus vaccine turns out to be ineffective, some brave volunteers, who would have lived, might die for nothing. I reject these ideas and argue that we should embrace challenge studies.
I have volunteered as someone willing to be a subject of such studies by registering with 1 Day Sooner, an organization created to promote challenge trials, and by writing to the National Institutes of Health expressing my interest in participating in vaccine studies, including challenge trials.
I emphasize that I do not feel particularly brave for volunteering like this. For one thing, I doubt that as a 71 year old I would be chosen for a challenge study, although I am eager to participate. The chances of my dying from a deliberate infection of coronavirus are not much different from the chances of a man of my age dying in the normal course of living. My motivation is that, as a scientist, I want the data, because with good data we make good decisions.
Counter arguments don't hold up
Why do I, and others, support COVID-19 challenge trials when plenty of good and thoughtful people reject them?
One argument against such trials is that it is unacceptable to sacrifice one individual for the benefit of many others. But our society does that routinely. We recruit young men and women into the military, putting their lives at risk to protect our national security. We allow astronauts to undertake risky spaceflight to gain knowledge that benefits everyone. (And make no mistake about the risks — one of my graduate school mates, Ron McNair, died in the Challenger accident. He knew the risks and accepted them gladly.) Why would we not allow willing volunteers in a vaccine trial the same opportunity for personal sacrifice that we routinely offer to soldiers, astronauts, and others?
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Another argument posits that while we allow the self-sacrifice of people like firefighters and organ donors, such risks are acceptable because those involved are confident of the good results of their risks, while challenge trial volunteers are not. This is a weak argument. Neither a first responder nor an organ donor can guarantee that her sacrifice will lead to the saving of a life. The building into which a firefighter rushes may collapse before she reaches any victims, and organs are frequently rejected.
Other arguments question whether challenge trials will produce useful and actionable results while putting volunteers at mortal risk. This is a legitimate concern, and requires that any challenge study be carefully designed, and probably means that only trials of multiple different vaccine candidates, ones whose efficacy is already determined to be likely to be high, be considered.
Informed consent is crucial. Volunteers must understand the risks. Furthermore, I would be uncomfortable with a campaign that actively recruited participants rather than one which drew upon people who, like me, have independently offered to take part. Similarly, I am suspicious of trials in which people are offered payment for participation, since this could easily constitute exploitation of the less advantaged members of our society. At the same time, I recognize the difficulties faced by people who would need to take time off work to engage in a study requiring isolation during the incubation period after infection.
Challenge trials for COVID-19 vaccines raise a lot of issues; we should consider them seriously and promptly in the interests of saving lives.
William D. Phillips is a 1997 Nobel laureate in physics.