This revolutionary technology shows you all the viruses you've ever had - and it could change medicine

Imagine walking into a doctor's office, getting tested for all the viruses you've ever encountered in your whole life, and getting your results before you left.

This would be game-changing for nipping contagious viruses without obvious symptoms (like Hepatitis C) in the bud and for illuminating how viruses (and our body's response to them) impact other diseases, like cancer.

That's what Harvard genetics professor Stephen Elledge envisions for the doctors' offices of the not-too-distant future, and his new study outlines just how to make it happen.

Using a single drop of blood, he and a team of researchers were able to run a test that reveals nearly every virus a person has ever been exposed to. According to some rough calculations done by one of the study's researchers, Tomasz Kula, the test could cost as little as $25 a pop.

While numerous tests exist for specific viruses in the body, this test is unique because it can spot all of them at once.

How it works

When you get a virus, your immune system unleashes a defense of special white blood cells called T and B lymphocytes. While some of the T cells help detect and kill invading viruses, others help the B cells, which make special proteins called antibodies. Those tag an invading cell for destruction.

Once your body beats the virus and effectively clears it from your system, some of these specialist T and B cells stick around and keep a "memory" of the destroyed virus to keep you protected from it.

You can think of these memories as harmless little photographs that your immune system carries around. The test the researchers made looks for these photographs and uses them to see the viruses you've had in your lifetime.

How it could change the future of medicine

If the test were incorporated into a regular doctor's visit, Elledge, the author of the new study, told Business Insider, it could help reduce the spread of contagious viruses that don't have obvious symptoms.

"There are people walking around with chronic Hepatitis C infections that have no idea they have them," said Elledge. "Now imagine if this was a routine test that was done every time you went to the doctor. With things like Hep C, the earlier you treat them, the better."

The test could also help illuminate how viruses (and our body's response to them) may impact other diseases.

In people with HIV who underwent the test, for example, Elledge found that their immune systems had responded far more intensely to almost every virus. That was a huge surprise, Elledge said, since HIV attacks and destroys the immune system.

That suggests a far more complex relationship between viruses and disease than has been imagined before. "There are a number of diseases that could be initiated by a viral infection, so it's an interesting idea to have a patient come in with a disease and say, let's take a look at what viruses they've been exposed to," said Elledge.

Other scientists who weren't involved in the research are pretty excited about it too.

Adolfo Garcia-Sastre, for example, a professor of microbiology and medicine and co-director of the Global Health and Emerging Pathogens Institute at the Icahn School of Medicine at Mount Sinai in New York told the New York Times he thought the new technology was "really amazing."

What they found

In addition to testing nearly 569 people across the US, South Africa, Peru, and Thailand, Elledge and his team of researchers did the test on themselves. "We all wanted to know," said Elledge.

They found that most people, over the course of their lives, encountered about 10 species of virus. Most of them were the ones that cause the common cold (rhinovirus), the flu (influenza virus), and diarrhea and respiratory illness (adenovirus).

But a few people in the study had some pretty high exposures: In at least two participants, they found evidence of at least 84 viral species.

The researchers also discovered some striking differences between people's viral exposure between countries. While people in the US tended to have pretty low rates of viral exposure, for instance, those living in the three other countries they studied tended to be a bit higher.

The scientists aren't sure yet why that is, but Elledge suspects it could have to do with the the genetics of geographically-distinct populations or a result of a higher percentage of people living in urban vs. rural areas.

The test isn't quite ready for the doctor's office just yet, of course.

For one thing, it still takes weeks to complete. Plus, it's not perfect - it can still miss some viruses, including past infections that the body's immune system is only responding to on a very low level.

The hospital Elledge hails from, Brigham and Women's Hospital, recently applied for a patent on the test, which the researchers named VirScan. Elledge is hoping a company will take on the test and streamline it to make it available to the general public.