They ask for an ethical framework to test the coronavirus vaccine infecting humans

They ask for an ethical framework to test the coronavirus vaccine infecting humans

Achieving the vaccine against the SARS-CoV-2 virus could be a near reality, but for this, controlled infection studies in people must be carried out. An international team is now calling for a consensus that takes into account the social value of these trials and the balance between risks and benefits.

In human controlled infection (CHI) studies, a small number of volunteers are deliberately exposed to infection so that scientists can quickly gather data on the efficacy of experimental vaccine candidates or treatments. This practice shortens the times for the necessary clinical trials.

The scientific community is considering implementing the CHI to accelerate the search for a vaccine against SARS-CoV-2. In March, three authors launched the idea in an article published in the magazineJournal of Infectious Diseases which generated an important ethical debate around the risk it entails for volunteers.

As Luis Guerra, former director of the National School of Health, clarified, “The question of how to speed up the long process of clinical research on vaccines is not new and has already been posed in a practical way years before we had this pandemic.”. These types of practices have already been used with success in diseases such as influenza, typhus, cholera and malaria.

Now, in the latest issue of the journal Science, an international group of experts outlines in a document the main lines of an ethical framework to carry out these CHI trials, in response to the COVID-19 pandemic.

According to the Colombian researcher Ricardo Palacios, director of clinical research at the Butantan Institute of São Paulo Brazil and one of the authors of the text, “We expose the experimental infection of human beings by SARS-CoV-2 as an ethically acceptable possibility, provided that the studies take into account aspects such as the social value of these trials, which should be translated into the development of drugs to prevent or treat COVID-19”.

Furthermore, Palacios says, “it is necessary to ensure that data and procedures are shared between the different research groups working on these challenge trials”.

Risks versus benefits

Another aspect that must be taken into account in his opinion is that “measures so that the risk-benefit of the CHI studies is reasonable”. This is obtained by choosing the appropriate participants, who must be healthy young people between the ages of 20 and 44 and with a lower risk of mortality from COVID-19. Further, "care protocols must be established to protect the participants and personnel involved in the research”, He emphasizes.

It will also be necessary to consider “la linking of different stakeholders, from the community where the study is carried out to the production companies and ethical and regulatory authorities. All of this is key for the study to be accepted and used in the best possible way.”, He says.

The authors also indicate that it is important to select the appropriate research center, as well as to establish a very rigorous consent process and adequate financial compensation for participants, in accordance with local ethical regulations.

Palacios and his fellow signatories of the document believe that the CHI studies generate very strong scientific evidence, but the mechanism of infecting people to enhance them remains very strange to the community. Therefore, these essays “They must be considered as an extraordinary option and should only be authorized when there are guarantees for the participants and the mechanisms are created so that the company has access to the benefits of the results”.

14,183 volunteers from 102 countries

Although it may seem strange that someone wants to expose themselves to such a dangerous disease for experimental purposes, an initiative, called 1Day Sooner, has already been launched, which already has 14,183 volunteers from 102 countries to undergo this type of CHI study, with the aim of to get a coronavirus vaccine. The organizing organization declares itself independent of the interests of groups and companies that develop vaccines against the pandemic.

According to Palacios, until now “the system of ethical and regulatory control in clinical trials of pharmaceutical products has been extremely rigorous throughout the world. Perhaps the pressure on ethics committees to have a less strict evaluation could be one of the biggest risks we face now”.

Because, "Articles such as the one published in Sience can help these committees to have references that support their reviews and thus can resist eventual undue pressure”, He concludes.


Seema K. Shah, Ricardo Palacioset al. "Ethics of controlled human infection to study COVID-19".Science (April 7, 2020)

Video: Human challenge trials being considered for Covid vaccine (October 2020).