WHAT IF ALL VIRUSES DISAPPEARED?

If all viruses disappeared, the world would be very different — and not necessarily for the better.

Viruses seem to exist solely to wreak havoc on society and bring suffering to humanity. They have cost untold lives over the millennia, often knocking out significant chunks of the global population – from the 1918 influenza epidemic which killed 50 to 100 million people to the estimated 200 million who died from smallpox in the 20th Century alone. The current Covid-19 pandemic is just one in a series of ongoing and never-ending deadly viral assaults.

If given the choice to magically wave a wand and cause all viruses to disappear, most people would probably jump at that opportunity, especially now. Yet this would be a deadly mistake – deadlier, in fact, than any virus could ever be.

“If all viruses suddenly disappeared, the world would be a wonderful place for about a day and a half, and then we’d all die – that’s the bottom line,” says Tony Goldberg, an epidemiologist at the University of Wisconsin-madison. “All the essential things they do in the world far outweigh the bad things.”

The vast majority of viruses are not pathogenic to humans, and many play integral roles in propping up ecosystems. Others maintain the health of individual organisms – everything from fungi and plants to insects and humans. “We live in a balance, in a perfect equilibrium”, and viruses are a part of that, says Susana Lopez Charretón, a virologist at the National Autonomous University of Mexico. “I think we’d be done without viruses.”

Nearly all virologists solely study pathogens; only recently have a few intrepid researchers begun investigating the viruses that keep us and the planet alive, rather than kill us.

“It’s a small school of scientists who are trying to provide a fair and balanced view of the world of viruses, and to show that there are such things as good viruses,” Goldberg says.

What scientists know for sure is that without viruses, life and the planet as we know it would cease to exist. And even if we wanted to, it would probably be impossible to annihilate every virus on Earth.

For a start, researchers do not know how many viruses even exist. Thousands have been formally classified, but millions may be out there.

Key to ecosystems

What we do know is that phages, or the viruses that infect bacteria, are extremely important. Their name comes from the Greek phagein, meaning “to devour” – and devour they do. “They are the major predators of the bacterial world,” Goldberg says. “We would be in deep trouble without them.”

Phages are the primary regulator of bacterial populations in the ocean, and likely in every other ecosystem on the planet as well. If viruses suddenly disappeared, some bacterial populations would likely explode; others might be outcompeted and stop growing completely.

Protective to humans:infection

with certain benign viruses even can help to ward off some pathogens among humans.

GB virus C, a common bloodborn human virus that is a non-pathogenic distant relative of West Nile virus and dengue fever, is linked to delayed progression to Aids in Hiv-positive people. Scientists also found that GB virus C seems to make people infected with Ebola less likely to die.

Likewise, herpes makes mice less susceptible to certain bacterial infections, including the bubonic plague and listeria (a common type of food poisoning). Infecting people with herpesvirus, bubonic plague and listeria to replicate the mouse experiment would be unethical, but the study’s authors suspect that their findings in rodents likely apply to humans.