According to US study results, blood transfusion rarely transmits human herpesvirus (HHV)-8.
Our study was not large enough to rule out HHV-8 transfusion transmission, but it did indicate that if it occurs it is very rare, told Dr. Sheila C. Dollard and Dr. Michael J. Cannon from Centers for Disease Control and Prevention, Atlanta.
Drs. Dollard, Cannon, and team conducted HHV-8 serologic testing among participants of the Transfusion-Transmitted Viruses Study (TTVS) to evaluated the possibility of HHV-8 transmission via blood transfusion.
Among transfusion recipients, the seroprevalence of HHV-8 six months after surgery was 7.1% and 7.7% among surgical control patients who did not receive transfusions.
The researchers reported that only two study patients met the definition of seroconversion. Among them, seroconverter patient had received only HHV-8-negative blood and the other was a surgical control patient who didn’t receive a transfusion.
According to investigators, none of the estimated 128 seropositive units (based on the 2.8% seroprevalence among blood donors) given to HHV-8-seronegative transfusion recipients resulted in seroconversion.
It was not especially surprising that there was no evidence of HHV-8 infection (seroconversion) in this setting because over the years, investigators have not detected HHV-8 virus in the large majority of healthy HHV-8 antibody positive people who have been tested for virus, such as blood donors, Dr. Cannon and Dr. Dollard explain.
There are two obstacles to conclusively establish HHV-8 transfusion transmission risk; because the US blood donor seroprevalence for HHV-8 is very low (about 4%), any study to evaluate the US transmission risk would need to be very large, they add. The second obstacle is that there is currently no high-throughput, highly sensitive antibody test for HHV-8 that would be needed for a large study with several thousand serum specimens.
Additional studies may still be warranted to exclude an exceedingly low risk of HHV-8 transmission in the United States, given that transmission via transfusion has been documented at 3% per seropositive unit in Uganda, where HHV-8 is hyperendemic and fresh nonleukoreduced blood is routinely transfused, write Dr. Michael P. Busch from University of California, San Francisco, and Dr. Simone A. Glynn from the National Heart, Lung, and Blood Institute, Bethesda, Maryland, in a related editorial.
However, they continue, Cannon et al.’s study should alleviate concerns over the need to screen donors for HHV-8 and to maintain MSM deferral to prevent transmission of the virus.