Does exposure to cold and flu viruses weaken or strengthen the immune system?

“Exposure and disease are two different things,” Murcia explained. “We get exposed to viruses and other pathogens all the time, and often we mount a response without even realising that it’s there. What I wouldn’t advise is deliberately trying to get infected, because every infection has a risk.”

  Why some labs work on making viruses deadlier — and why they should stop

The pandemic should make us question the value of gain-of-function research.

  The 12 deadliest viruses on Earth

Humans have been battling viruses since before our species had even evolved into its modern form. For some viral diseases, vaccines and antiviral drugs have allowed us to keep infections from spreading widely, and have helped sick people recover. For one disease — smallpox — we've been able to eradicate it, ridding the world of new cases. But we're a long way from winning the fight against viruses.

  Viruses Can Help Us as Well as Harm Us

Experts are figuring out how to exploit the 380 trillion viruses that make up the human virome.

  Viruses: the Ugly, the Bad, and the Good

Some of these biological agents are being recruited to combat bacterial infections.

 Children Aren’t Getting More Respiratory Viruses — It Just Seems That Way

Deaths and paralysis stemming from respiratory infections have been reported, but those cases are rare.

 Some viruses travel in vehicles made of our cells to make us sicker

Researchers report that two causes of the stomach flu, norovirus and rotavirus, appear to work better in groups. Specifically, they seem to travel together in little biological packages, or vesicles, made out of parts of our own cells. That lets them fly under the radar of our immune system, passing easily into our cells. Preliminary work has shown handful of other viruses, including the poliovirus and the rhinovirus (which causes the common cold), move through the body in this way.

 The World Is 'Grossly Unprepared' for the Next Big Virus Outbreak, Study Finds

Which is a problem, because infectious diseases are projected to become only more common.

 There Are More Than 380 Trillion Viruses in Your Body at Any Time

Viruses on your skin? Check. Viruses in your lungs? Check. Viruses in your pee? Check.

 This Is What It Would Take to Turn a Virus Into a Weapon

“A well-funded organization with scientific expertise and the resources to grow, manipulate, or release agents, and the motivation to actually use them—that’s the worst case scenario."

After Ebola

As Quammen puts it, every emerging virus “is like a sweepstakes ticket, bought by the pathogen, for the prize of a new and more grandiose existence. It’s a long-shot chance to transcend the dead end. To go where it hasn’t gone and be what it hasn’t been. Sometimes the bettor wins big.”

A Brief, Terrifying History of Viruses Escaping From Labs

How well-intentioned research with dangerous pathogens could put people at risk.

A Federal Ban on Making Lethal Viruses Is Lifted

Federal officials on Tuesday ended a moratorium imposed three years ago on funding research that alters germs to make them more lethal. Such work can now proceed, said Dr. Francis S. Collins, the head of the National Institutes of Health, but only if a scientific panel decides that the benefits justify the risks. Some scientists are eager to pursue these studies because they may show, for example, how a bird flu could mutate to more easily infect humans, or could yield clues to making a better vaccine. Critics say these researchers risk creating a monster germ that could escape the lab and seed a pandemic.

Are Viruses Alive?

Although viruses challenge our concept of what "living" means, they are vital members of the web of life.

Are viruses alive? New evidence says yes

Evolutionary history suggests they evolved from ancient cells.

Harder Evidence Builds That Viruses Play a Role in Alzheimer's

A study seeking new drug targets for the disease unexpectedly implicates two types of herpes.

How Do Viruses Evolutionarily Benefit From Making Us Sick?

As a general rule, viruses don’t benefit from making us ill. They would much prefer* to keep us healthy. What benefits the virus is making copies of itself and spreading those copies to new human hosts.

Instead of Killing Mosquitoes, Why Don’t We Edit the Viruses Out of Them?

We’re desperate for a solution. What are our options?

Viruses Might Offer New Help in Treating Cancer

Unmasking viral genes in our DNA may trigger an immune response that destroys cancer cells.

Where did viruses come from?

Tracing the origins of viruses is difficult because they don't leave fossils and because of the tricks they use to make copies of themselves within the cells they've invaded. Some viruses even have the ability to stitch their own genes into those of the cells they infect, which means studying their ancestry requires untangling it from the history of their hosts and other organisms.

Why Viruses Kill More Men Than Women

Men are more vulnerable to certain diseases than women. The pathogens that are more deadly in the less-fair sex include one that causes tuberculosis, as well as the viruses that can ultimately lead to tonsil cancer (namely the HPV virus) and Hodgkin's lymphoma (Epstein-Barr virus). In a new study, scientists have shown for the first time that this might not be blamed on weaker immune systems in men, but rather on the fact that viruses actually take it easier on women.