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Labs all over the world are scrambling to create a vaccine against COVID-19. It’s the world’s best hope for defeating the ongoing coronavirus pandemic — and politicians know it. Many, including President Trump, insist a vaccine will be available in months. The White House has created “Operation Warp Speed” to make a vaccine a reality.

The political spin promising a quick vaccine is false. The average time to make a vaccine is 20 years starting from animal models to small-scale safety studies, and then to full, lengthy clinical safety and efficacy trials. Even with many groups working on vaccines, the usual way of developing them is likely to prove slow.


One reason the process is slow is that large clinical trials rely on natural infection with the virus to see if a vaccine works and is safe. Thousands get the test vaccine, but then researchers must wait for these subjects to be infected naturally while at the same time telling them how to minimize that risk. It can take years to see enough cases to know if a vaccine is truly safe and effective.

But there is an option, rarely used, which could generate solid data while speeding the process up significantly — a challenge study. This involves recruiting a few hundred people, vaccinating them with test vaccines, then deliberately giving them a manufactured dose of the COVID-19 virus. After exposure, the subjects would be isolated in a hospital or clinic to observe them for a few months. We have the know-how now to run such a study. And the benefit would be many months, if not years, saved to study different candidates. The hurdle is obvious — is it ethical to give someone a deadly disease?

In a pandemic, yes. The number of people who will die from the novel coronavirus while the hunt for a vaccine plods on is exponential. And if the virus ebbs and returns, it will take even longer to learn anything. The stakes are so high that risking volunteers makes sound moral sense.


So if challenge research is ethical how should it be done?

Subject Selection In doing challenge work, it is obligatory to minimize the risks subjects will face. For challenge studies involving COVID-19, this means enrolling those with the lowest likelihood of being harmed. Studies show healthy adults aged 20 to 29 have a 0.03 percent risk of death and a 1.1 percent risk of hospitalization when infected by the virus. If that segment of the population volunteers, all available interventions such as antivirals and antibodies must be at hand to use should the participants become ill.

Consent The key requirement for participation in all research is that the subjects involved volunteer without coercion or pressure. Participants must be fully informed of all risks and unknowns they may face, must demonstrate they understand those risks, and must be aware that challenge studies are not intended to provide benefit to them. They must be motivated by a desire to altruistically help others by creating knowledge and data.

Risk Is the risk being asked beyond reasonable risk? No. Health care workers and staff treating infected persons face the risk of death and illness, but we permit them to assume those known risks to try to save others. Living donors of kidneys and lobes of liver face greater risk than those potentially confronting volunteers for SARS-CoV-2 challenge studies.


The overall case for initiating challenge research is convincing. Thousands of people have already said online they will volunteer. It’s time to fund the necessary preparations for doing challenge studies. Our lives depend on it.

Arthur Caplan is a professor and founding head of the Division of Medical Ethics at NYU School of Medicine in New York City.