The Blood Virome: A new frontier in biomedical science

Recent advances in metagenomic testing opened a new window into the mammalian blood virome. Comprised of well-known viruses like human immunodeficiency virus, hepatitis C virus, and hepatitis B virus, the virome also includes many other eukaryotic viruses and phages whose medical significance, lifecycle, epidemiology, and impact on human health are less well known and thus regarded as commensals. This review synthesizes available information for the so-called commensal virome members that circulate in the blood of humans considering their restriction to and interaction with the human host, their natural history, and their impact on human health and physiology.