WASHINGTON People infected with the herpes simplex virus shed virus no matter how long they have been infected or how frequently they have outbreaks, according to data from adults aged 18 years and older with newly acquired and long-term herpes infections.
Previous studies have suggested that herpes recurrences are more frequent within the first year after infection, and that viral shedding occurs on nearly 40% of days in patients with herpes simplex virus (HSV) infection for 6 months or less, said Clare A. Brennan and Cathy K. Heitman, Ph.D., of the infectious diseases medicine development center for GlaxoSmithKline in Research Triangle Park, N.C.
But the current study is the first to show a viral shedding rate on more than 50% of days in patients with new infections, they noted.
To study the natural history of viral shedding in patients with HSV-2, the researchers conducted a post hoc analysis of a placebo group of 69 patients who were part of a larger study that compared valacyclovir, acyclovir, and placebo. The group comprised 27 patients who had had HSV-2 for 6 months or less, and 42 patients with HSV-2 for longer than 6 months and at least six recurrences per year. The new-infection group comprised 9 men and 18 women, and the established-infection group comprised 18 men and 24 women.
The researchers presented their results in a poster session at the jointly held annual Interscience Conference on Antimicrobial Agents and Chemotherapy and the annual meeting of the Infectious Diseases Society of America.
Overall, subclinical shedding was more than twice as high in patients with newly acquired infections as it was in those with established infections (31% vs. 14%, respectively).
When the researchers examined subclinical shedding as a function of HSV-2 duration, the rate of subclinical shedding was 33% in 29 patients diagnosed within a year, 14% in 17 patients infected for 15 years, 15% in 9 patients infected for 610 years, and 11% in 13 patients infected for 11 years or longer. (Complete data were not available for one patient.)
Patients with the least number of outbreaks shed virus at the highest rate, the researchers noted. The percentage of days with subclinical shedding for the patients who had 03, 45, and more than 5 outbreaks within the past 6 months was 24%, 17%, and 16%, respectively.
The results suggest that people with few HSV outbreaks or with long-term infections are not exempt from subclinical shedding, and they could still transmit the virus to an uninfected partner, the researchers noted.
The study was sponsored by GlaxoSmithKline.