Vaccine and Infectious Disease Division

Exploring HSV Viremia

While herpes simplex virus (HSV) infection in healthy people often results only in mouth or genital ulcers, the virus can occasionally spread to the rest of the body.  HSV viremia, or the presence of the pathogen in the blood, is more common in immunocompromised patients but can occur in healthy subjects on occasion.  Until now, it has not been known what the consequences of this viral spread are for healthy or immunocompromised people.  Now, a group of researchers from VIDI and the University of Washington, led by VIDI assistant member Dr. Corey Casper, have looked at five years of past HSV data from the UW Molecular Virology Laboratory and the correlation of HSV viremia with different health outcomes in these patients’ medical records.  The scientists found that patients with HSV viremia often die, although it is not clear whether HSV viremia directly causes death.

The laboratory detects HSV (and other viruses) by looking for viral DNA using a sensitive technique, polymerase chain reaction, or PCR.  The laboratory has performed diagnostic lab tests for many Seattle area hospitals since 2000.  The researchers looked at data from 2001 to 2006 where the laboratory tested blood samples of 951 patients for HSV.  They found 13 adult subjects who tested positive for HSV viremia and whose medical records were available.

Of these 13 patients, only four are still alive today.  Of the nine who died, two-thirds were immunosuppressed.  Many of those who died suffered sepsis and failure of multiple organs.  However, it is not clear whether HSV caused these problems, or was merely along for the ride.  Some patients also suffered from other health problems, such as central nervous system infections, fever, and hepatitis.  These results imply that HSV viremia may have severe clinical outcomes for both immunosuppressed and immunocompetent patients. However, prospective studies, where patients are followed with the intent to study the effects of HSV viremia rather than searching through past records, are needed to understand the true effects of this infection.

Clinical correlates of herpes simplex virus viremia among hospitalized adults.  Berrington WR, Jerome KR, Cook L, Wald A, Corey L, Casper C.  Clin Infect Dis. 2009 Nov 1;49(9):1295-301.