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As COVID-19 takes over the entire world, researchers have been scrambling to develop a vaccine over the last several months. Copious trials and tests have been conducted and now, in 2021, various companies are finally releasing their version of a vaccine with about a 95% success rate. However, during the process of creating this vaccine, multiple challenge studies and tests were conducted. A human challenge study is a type of study where researchers deliberately infect participants with a virus to test the efficacy of possible vaccines. Therefore, there is a multitude of risks associated with this, as purposely infecting individuals can cause uncertain harm towards them and a perfectly healthy person could become sick. 

One specific human challenge study is conducted for the SARS-CoV-2, the specific strain of coronavirus that caused COVID-19, vaccine. During this study, a group of participants had to agree to be infected with COVID-19 and be used as test subjects to gauge the efficacy of various vaccines.  Phase I tests the safety of the vaccine and uses a small group of participants. Then, phase IIa studies the dosage trials given to people who have the virus, while phase IIb is used to test the efficacy of the vaccine compared to a placebo. Phase III is the big trial where the vaccine is given to a large group of people to test its safety and potency (Schaefer et al. 2020). Finally, once the vaccine is developed, a fair distribution plan must be created because of its global high demand (Liu et al. 2020). In order to develop a fair and ethical distribution plan, the intended goals of the vaccine trial must be considered (Gupta et al. 2021). Who would benefit from getting the vaccine first? How quickly should the vaccine be distributed? Who qualifies as “high-risk”? All of these questions are carefully considered in order to determine who should be prioritized to create the most ethical allocation process (Gupta et al. 2021). Without creating a plan for the allocation of the vaccine, individuals who have a crucial need for it may not receive it in time, resulting in even more casualties.

Although a specific experiment was not conducted, the ethical issues associated with a human challenge study are heavily considered by researchers at the National University of Singapore and the University of Oxford. After studying the moral concerns of a COVID-19 human challenge study, they determined that the study could have drastic repercussions due to the increased harm to participants. For instance, if any of the volunteer participants were to experience significant side effects or even death from deliberate exposure to COVID-19, there would be copious implications associated with the development of the vaccine. Therefore, if these studies must continue, all participants must consent and be informed of any new details in regards to the study. Additionally, all “critical care resources” must be fairly prioritized to the participants to ensure that everyone is “assessed equally based on short- and long-term survival prospects” (Schaefer et al. 2020). In regards to funding for the human challenge study, the researchers did not receive any grants from funding agencies “in the public, commercial, or not-for-profit sectors” (Schaefer et al. 2020). However, the Victorian State Government did provide some funding to support the research done on the study due to one of the author’s involvements in a research institute.

After researching and conducting various trials for several months, multiple companies have finally released their version of a vaccine to diminish a pandemic that has taken over everyone’s lives for over a year.  Not only has it changed everyone’s lifestyles, but it has also caused thousands of casualties worldwide. Therefore, people have been yearning for a vaccine for several months in hopes of normalcy. After studying the implications of a human challenge study to create a COVID-19 vaccine, researchers determined that it could be dangerous since it involves intentionally infecting individuals. Therefore, this study could be improved and remove some ethical implications if the vaccine were tested on individuals who have already been naturally infected by the vaccine, as the overall study would not be risking a healthy person’s life. Several processes have to occur in order to create a successful vaccine and now that something has been developed, individuals globally may finally return their lives to normal, or at least close to it.



Liu Y, Salwi S, Drolet BC. Multivalue ethical framework for fair global allocation of a COVID-19 vaccine. Journal of Medical Ethics. 2020;46(8):499-501. doi:10.1136/medethics-2020-106516

Google Images, Creative Commons license

Gupta R, Morain SR. Ethical allocation of future COVID-19 vaccines. Journal of Medical Ethics 2021;47(3):137-141.

Schaefer GO, Tam CC, Savulescu J, Voo TC. COVID-19 vaccine development: Time to consider SARS-CoV-2 challenge studies? Vaccine. 2020;38(33):5085–5088. doi:  


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