According to a research article published in the latest issue of Science, a new, still-experimental blood test called VirScan can identify almost every virus you've ever been exposed to, by testing only a single drop of your blood. Better still, this test is expected to only cost $25 to perform.
On June 5, Science published a research article discussing “Comprehensive serological profiling of human populations using a synthetic human virome.” The study's senior author is Stephen Elledge, a professor of genetics and medicine at Brigham and Women's Hospital and Harvard Medical School.
Elledge admits that the current version of the test has some limitations – it can overlook smaller viruses, or miss past infections for which the immune response has dwindled, but the test can apparently detect signs of exposure to over 1,000 strains from 206 different species of virus — almost every virus known to infect humans.
The study's abstract page offers a brief explanation of how this works: “In addition to causing illness, viruses leave indelible footprints behind, because infection permanently alters the immune system. Blood tests that detect antiviral antibodies can provide information about both past and present viral exposures.” But researchers “developed a blood test that identifies antibodies against all known human viruses” by “[u]sing a synthetic representation of all human viral peptides.”
Peptides are combinations of amino acids, and amino acids are what combine to make various proteins. A virus, meanwhile, is essentially just a scrap or genetic material, either DNA or RNA, wrapped in a protein shell.
Viruses are not considered living organisms in their own right, because they cannot reproduce by themselves (or in conjunction with other members of their species). Viruses can only reproduce by invading the cells of living organisms – usually plants, animals or bacteria – and then commandeering those living cells to produce new copies of the virus.
When you get a virus, your immune system (ideally) responds by producing special proteins called “antibodies” to fight the viral infection. But traces of those antibodies will remain even after you've beaten that virus, which means you now enjoy what's called “acquired immunity” to that virus: even if you're exposed to that particular virus again, your immune system knows how to produce the necessary antibodies and fight off the virus before you even feel sick.
Consider the viral disease people call “the common cold” even though it's technically inaccurate to talk about the common cold, because it's not a single disease. There are over 200 different viruses that cause cold-like symptoms in people, and once you've had a particular cold virus, you then enjoy acquired immunity to it.
Something going around
This explains, among other things, why young children seem to catch colds all the time, whereas middle-aged and older adults rarely do: all else being equal, the older you are, the more colds you've already had and thus the more acquired immunities you've collected. It also explains the occasional mystery “Seems like everybody in my social circle caught a nasty cold — except me. I wonder why I didn't catch it?” Maybe it's because you already had that particular strain of cold virus a few years ago, and acquired immunity before your current companions did.
(Vaccines, meanwhile, work by using dead or weakened strains of certain viruses to stimulate the immune system into producing the right strain of virus-fighting antibodies without actually suffering from the viral infection.)
So if your doctor wants to know whether you have or had a particular viral infection, it's relatively easy to find out by looking for those virus-specific antibodies in your blood. But VirScan promises to vastly streamline this process by testing not merely for one viral antibody, but almost all of them. This not only makes it easier to determine a patient's full viral history, but will also make it easier to detect and treat certain viral infections before the patient even shows symptoms.
For example, people with hepatitis C have a pretty good prognosis if they are treated right away — but the disease usually takes awhile to develop noticeable symptoms, and by the time that happens the infection's advanced enough to be difficult to treat.
Better treatment options
In addition to improving treatment options for individual patients, VirScan also promises to make it much easier for researchers to study the overall history and development of certain diseases – how do they spread, and which populations are most vulnerable. It can also further research to study whether individual viruses or the body's own immune response to them could in turn lead to other diseases, or even in the development of certain cancers.
As Stephen Elledge said, “I'm sure there’ll be lots of applications we haven’t even dreamed of. That’s what happens when you invent technology — you can’t imagine what people will do with it. They're so clever.”
According to a research article published in the latest issue of Science, a new, still-experimental blood test called VirScan can identify almost every vir...