Though 75% to 90% of HSV-2 infected persons may be unaware of their condition, they may still be capable of transmitting the infection. A recent study investigates the patterns of viral shedding and presumed infectivity in “asymptomatic” HSV-2 (i.e. HSV-2 in persons unaware of their condition prs to diagnosis) as against “symptomatic” infection. The occasion seems to have been offered by a group of 88 asymptomatic persons whose status emerged during a previous trial. These, along with a group of 410 symptomatic persons, were instructed to inspect the genital region for lesions daily and obtain swabs.
What do we learn? Overall, viral shedding in the asymptomatic participants took place in 10.2% of days, as opposed to 20.1% (risk ratio for asymptomatic group on adjusted multivariate model = 0.57). Shedding occurred sub-clinically both in asymptomatic and in symptomatic, though less than in asymptomatic participants (8.5% vv. 12.9%, RR = 0.66); and it also occurred in the presence of lesions in asymptomatic as well as symptomatic (3.8% vv. 13.8%, RR = 0.28), since lesions were detected by 19 of the 88 asymptomatic participants in the course of the follow-up. Presence of lesions impacted on infectivity through increased duration of episodes of viral shedding. Asymptomatic differed from symptomatic infection in the frequency of these episodes of greater duration. For those in the asymptomatic group who reported lesions, shedding rate was 18.7 % as against 7.6% for those in the asymptomatic group who reported no lesions.
What are the implications of this study? The authors claim to be addressing a management problem posed by the situation of “asymptomatic patients with an HSV-2 seropositive test result”. Given the mildness of the condition, we might ask whether this “management problem” is created by the HSV-2 infection or the seropositive test result! So it is disconcerting to find a Swedish health researcher on Herpes using findings from this study (and her own) in order to urge us not to “wait for sores to appear or other visual symptoms” but to “go get checked out” (http://www.medicalnewstoday.com/articles/222161.php). Is this really a sensible reaction to the findings of this trial?
Elizabeth Tronstein et al., “Genital Shedding of Herpes Simplex Virus Among Symptomatic and Asymptomatic Persons With HSV-2 Infection”, Journal of the American Medical Association 2011;305(14)