In the realm of public health, we frequently hear about virus eradication — a term defined by the Center for Disease Control as "permanent reduction to zero of the worldwide incidence of infection caused by a specific agent as a result of deliberate efforts." Extinction, on the other hand, occurs when a virus no longer exists in nature at all — a status that is difficult to scientifically confirm considering the tendency for viruses to hide out in animal reservoirs until the next “spillover event.”

 Certain strains of the flu came to exist in this gray area of possible extinction after COVID-19 safety measures abruptly halted their spread (and potentially wiped them off the face of the Earth). The pandemic has also aptly demonstrated how different variants of a virus compete for supremacy and can cause one another’s extinction (if you’re interested in seeing the ebb and flow of different SARS-CoV-2 variants throughout the pandemic, check out the collection of infographics on CoVariants.org). Man-made vaccines, meanwhile, are arguably the most important route to virus extinction, and a universal coronavirus vaccine is top of mind for many in the scientific community. Read more here about the difficulties that lay ahead for that medical milestone.