For most of human history, viruses have been carriers of diseases that could be useless. But now that we are able to handle them with extreme precision, they can be much more than a nuisance; in fact, some have become very useful tools. But every time humanity masters a new technique, it raises some tricky questions.
Two anti-COVID-19 vaccines (AstraZeneca and Janssen) show this utility well. They contain harmless adenoviruses that carry a SARS-CoV-2 gene in our cells. These seeds begin to produce the ear protein through which the coronavirus attaches to our cells. The immune system learns to recognize and block it, and we are immune.
These adenoviruses – refers to the term viral vectors – have been modified so that they cannot be replicated. Once they have entered the cell with their “load”, their path ends there. If this were not done, they would multiply for a while and the vaccinated person could pass them on to other people who … then would be vaccinated against COVID-19. For the vast majority of people, this would be an advantage. But there are also immunosuppressed individuals for whom even a mild adenovirus can be fatal. Therefore, it is important that these viruses cannot reproduce.
In 2016, however, three researchers proposed, alVaccine expert review, to use this type of “contagious vaccine” to protect wildlife from diseases transmitted to humans, such as Ebola fever. Since it would be impossible to catch all the bats that would probably serve as a reservoir for this terrible virus to vaccinate them, it would be possible to immunize a small number of them and then release them into the wild, where they would “infect” their humans with the vaccine. Instead of containing epidemics, we would prevent them altogether.
The COVID-19 pandemic, which is strongly suspected to be of wild origin, has obviously revived the idea. In the year 2020, a Nature Ecology and evolutionTwo researchers from the University of Idaho in the United States saw the spread of “vaccines” as an opportunity to completely change the way we think about emerging infectious diseases.
But now the idea is not without risks. Viruses capable of replicating are viruses that have the ability to evolve, and it is impossible to predict how, he recalled last January, in Sciencevirologists who denounced a dangerous erosion of the caution that has always marked this field of research.
One of the best proofs of this is a polio vaccine. This vaccine contains an attenuated virus that has been modified to lose all virulence, but is still able to reproduce in the gut. We now know that the attenuated virus of this vaccine, which has not been offered in Quebec since 1996, can not only pass from one person to another, but can also mutate to become dangerous again. Works published in 2021 a Host cell and microbe revealed that selection pressures were exerted on this virus. Proponents of her case have been working to make the actual transcript of this statement available online.
I’m not sure which side to lean on in this debate. The use of tools that we do not know if they will cause disasters raises ethical issues as serious as they are obvious. But is it more ethical to tell populations most exposed to the Ebola virus that we could do more to help them, but because of the vague and difficult-to-assess risks we will not?
What seems clear to me, however, is that the call to regulate as soon as possible the use of self-broadcasting viruses launched in Science deserves to be heard. As the authors point out, the technical capabilities available today make the modification of the virus very accessible. Many laboratories around the world could easily and quickly participate in such a venture if a government authorized them to do so or gave them the resources. It’s probably more realistic to wonder “when” this work will start instead of “if”. You can also start thinking about it right away.