Viral History in a Drop of Blood

With VirScan, scientists can run a single test to determine which viruses have infected an individual.

Using VirScan, researchers detected an average of 10 viral species per person. (Photo by Eugene Bochkarev)

With just a single drop of blood, a test can reveal if someone has ever been infected with any of more than 1,000 different viruses.

Using a device called VirScan, researchers from BWH and Harvard Medical School can simultaneously check for the viruses, unlike standard blood tests that check for one pathogen at a time. The test does this by screening blood for virus-specific antibodies that are produced during an immune response, which the body continues to produce for decades afterward. The researchers detected an average of 10 viral species per person during their study.

“A viral infection can leave behind an indelible footprint on the immune system,” says study author Stephen Elledge, PhD, a principal investigator in BWH’s Division of Genetics and the Gregor Mendel Professor of Genetics and of Medicine at Harvard Medical School. “Having a simple, reproducible method like VirScan may help us generate new hypotheses and understand the interplay between the virome and the host’s immune system, with implications for a variety of diseases.”

While the test can be performed for about $25 per blood sample, it is currently only being used as a research tool and is not yet commercially available.