COVID-19: Experts emphasize the importance of ethics when testing coronavirus vaccines

The grassroots organization, 1Day Sooner, has asked people to show their willingness to volunteer in the COVID-19 Human Challenge study. They believe that challenging studies that intentionally expose healthy people to infection may accelerate vaccine development.

1Day Sooner reports that more than 35,000 people from 160 countries, including Canada, are ready to volunteer to be exposed to COVID-19.

But do we need to allow them?

Many find the idea of ​​human challenge research to be amazing. Why do scientists want to expose healthy volunteers to infectious diseases? One of the reasons is to efficiently conduct preliminary trials of new vaccines.

In the Vaccine Challenge study, participants are given either a new vaccine or a placebo and then intentionally exposed to an infectious agent. There is preliminary evidence that the vaccine works when the number of people who receive the vaccine is small compared to the placebo group.

Challenge studies have traditional clinical trials in mind. In clinical trials, patients receive new treatments that may improve their condition. There are risks from treatment, but those risks are offset by the outlook for direct benefit to the patient.

In contrast, challenge studies aim to deliberately get sick in healthy volunteers and have no direct benefit. Challenge research does not benefit volunteers, thus limiting the risk of volunteers being exposed for scientific purposes.

Ethical research

Can Vaccine Challenge Studies, including COVID-19, be conducted ethically? According to the current ethical guidelines, published in 2016 and co-authored by me, the ethical acceptance of challenge studies includes compelling scientific evidence, minimal risk to participants, and human details. There are various requirements, such as ethical guidelines for informed consent. Challenge research.

An important provision requires that “volunteers are not at risk of irreversible, incurable, or even fatal infections under any circumstances.” A challenge study was used to develop a vaccine for cholera and malaria, but this study was tolerated because there are drugs that can reliably treat both diseases.

However, the proposal to carry out a COVID-19 challenge study does not meet this important ethical requirement. The mortality rate for COVID-19 in Canada is 7.3%. Even if the challenge study is limited to adults in their twenties, the risk of death is 0.03%, or 1 in 3,000 patients.

Although the main effect of COVID-19 appears to be in the lungs, it is now clear that the disease affects many organs and leaves some patients with permanent damage. There is no cure for COVID-19 yet.

Challenging ethics

Researchers argued that widely accepted ethical standards should be changed to enable COVID-19 challenge research, which significantly speeded up the development of the COVID-19 vaccine, As a result, “life savings are in the thousands or perhaps millions.”

In a recent TED talk, bioethicist Nir Eyal argues that the permissible risk threshold in challenging studies is too low. Donating kidneys to people in need of a transplant is allowed, but at the risk of dying 1 in 3,000 donors.

Would you like to allow healthy volunteers to agree on similar risks in the COVID-19 Challenge Study?

Move forward safely

Neither of these arguments is convincing. There is reason to doubt that the COVID-19 Challenge study will actually give us the vaccine sooner. It usually takes one or two years of development to proceed with challenging research with new infectious agents. For COVID-19, scientists need to standardize the virus strain and determine a dose that reproducibly causes mild illness but not severe illness.

On the other hand, standard means of vaccine research and development are advancing rapidly. More than 160 vaccine candidates have been identified, 30 of which are currently being tested in human clinical trials. The two vaccine trials enrolled thousands of volunteers in Brazil, South Africa, the United Kingdom, and the United States.

Philip Dormitzer, Chief Scientific Officer at Pfizer Vaccines Research and Development, recently commented:

Maintaining trust

What about the claim that the permissible risk threshold in challenge studies is too low? The discussion here relies on an analogy between donating the kidney and participating in a vaccine challenge study. This assumes that the two cases are equivalent. is not.

Decades of experience in kidney transplantation mean that the risks to donors are well understood. Our experience with COVID-19 is very short and there is little information about the long-term effects of infection.

In addition, kidney transplants from closely matched donors are likely to be successful. The benefits of vaccine challenge studies may be much less, as only a small number of vaccine candidates will eventually be allowed to use (based on experience with other diseases).

Over the last 50 years, thousands of people have volunteered for challenge research. Participants have tolerated diarrhea from cholera and malaria fever, but no one has died. This is a testament to the skills and extraordinary efforts of scientists to protect volunteers. Scientists strive not only to protect volunteers, but also to maintain public confidence in scientific companies as they draw the line to “risk of irreversible, incurable, or deadly infections.”

I am worried that if the ethical standards are lowered and the COVID-19 Challenge study is allowed to proceed, volunteers will suffer irreparable harm and die. This carries the risk of undermining public confidence in both research and vaccines. Public trust is and will continue to be an integral part of our efforts to defeat COVID-19.

Charles Weiger, Professor of Medicine, Epidemiology and Biostatistics, Philosophy, Western University

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