Letter to the Editor: Should Viruses Exist? A Brief Reflection on the (Re)evolution of the Virus–Life Relationship

To the Editor:

“Should viruses exist?”—It is an obviously playful issue, considering the history will not change regardless of any answer. Despite this, this issue leads us to reflect on our relationships with viruses, listing the positive and negative aspects of their existence, so the question may be answered appropriately. This exercise may help us change the perspective of the virus–host interplay, encouraging us to adopt a beneficial reading of viruses, that is, how can they be subverted to meet our needs? Hereunder, we point out and discuss some negative and positive impacts of the virus existence, as well as the virus–life interaction, highlighting how this relationship has changed over the years and how to get closer to “Yes” to the proposed question: “Should viruses exist?”

Without delving into the negative impacts on life in its most varied aspects, the potential threat of viruses is the main and perhaps only argument to answer “No” to the question raised. Although small in number, the strength of this argument is sufficient by itself; after all, what could be more valuable than life? In contrast, the “Yes” list is far more extensive and, paradoxically, also includes strategies for promoting and maintaining life, in addition to expanding the limits of science. Indeed, the “Yes” list is essentially disruptive.

The biotechnological contribution of viruses, in their countless applications, is perhaps the first argument on the “Yes” list. The discovery of reverse transcriptase in retroviruses, for example, forever changed the knowledge and practice of molecular biology (Coffin and Fan, 2016). Moreover, viral vectors are one of the main tools for gene therapy, in addition to being a promising platform for delivering vaccine antigens against several microorganisms, as well as for oncolytic therapy (Bin Umair et al., 2022).

Viruses may also be an alternative to drawbacks related to antibiotic therapy, for pest control and as an alternative source of energy through piezoelectricity, offering a series of advantages over traditional methods (Lee et al., 2012; Wagemans et al., 2022). When considering this scenario, it is plausible to conclude that if viruses represent a potential threat to life and its attributes, they also act as a driving force for the improvement of science and technology, with a positive impact on human, animal and environmental well-being.

In addition to practical applications, viruses may contribute to the evolution and perpetuation of life. For example, viruses act in the cycling of marine nutrients, such as nitrogen, contributing to the equilibrium of the sea ecosystem (Wang et al., 2022). Furthermore, about 8% of the human genome has viral origin (Lander et al., 2001), so it is reasonable to speculate that viruses contributed to human biological evolution. This ambiguous participation of viruses in the life cycle, when analyzed in depth, makes it difficult to decide whether the balance of the virus–life relationship would be positive or negative.

Overall, despite the previous considerations, and even though the answer to the question “Should viruses exist?” does not change history, ongoing (and perhaps endless) efforts to increase the “Yes” list have the inherent consequence of improving lives. Indeed (and fortunately), it is reasonable to speculate that the “Yes” list will continue to grow, whereas the “No” list will likely remain the same. Finally, even with all the cons, we know where living with viruses has taken us. The other scenario, however, is uncharted territory and one question will likely remain unanswered indefinitely: Where and how would we be without viruses? Would it be worth the risk?