"At least 70% of the population shed HSV-1 asymptomatically at least once a month, and many individuals appear to shed HSV-1 more than six times a month. Shedding HSV-1 is present at many intraoral sites, for brief periods, at copy numbers sufficient to be transmitted, and even in seronegative individuals."
Just in case your haredi rabbi says there is no evidence that herpes can be transmitted by metzitzah b'peh (MBP) – the direct oral-to-genital sucking done by many haredi mohels to the baby's bleeding penis after removing its foreskin – even though babies have died and been maimed by herpes infections transmitted through MBP, or if he says that a mohel who has no outward signs of herpes can safely do MBP, you can cite this study, which shows both claims of your rabbi to be false:
Abstract: Asymptomatic Shedding of Herpes Simplex Virus (HSV) in the Oral Cavity
Howard E. Strassler, DMD
Jan. 27, 2009
Miller CS, Danaher RT. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2008;105(1):43-50.
Objective: The aim of this study was to investigate the rate of herpes simplex virus (HSV) shedding from the oral cavity, because recent studies suggest that shedding is more frequent than originally reported. Factors that could influence the rate and duration of shedding from the oral cavity were examined.
Methods: Existing epidemiologic data from 22 reports of HSV shedding from more than 3,500 individuals were analyzed with regard to demographics, frequency of sampling, and methodologic assays.
Results: HSV-1 was more likely to be detected than HSV-2 in the oral cavity of asymptomatic persons (7.5 odds ratio, 95% confidence interval 4.4–12.8; P < .0001). The rate of shedding was highly variable among individuals, ranging from none to 92% of the days tested, and occurred in seropositive and seronegative individuals. In cell culture studies, the rate of detection on a single day was 6.3%. Polymerase chain reaction studies provided a different picture. HSV-1 DNA was present in 97 of 180 patients (53.9%) at multiple visits, with a rate of daily detection of 33.3%. The mean duration of shedding was between 1 and 3 days, but more than 3 days in about 10% of the patients.
Conclusion: At least 70% of the population shed HSV-1 asymptomatically at least once a month, and many individuals appear to shed HSV-1 more than six times a month. Shedding HSV-1 is present at many intraoral sites, for brief periods, at copy numbers sufficient to be transmitted, and even in seronegative individuals. The dental implications of these findings are discussed.
Herpes simplex virus (HSV) is a significant human pathogen infecting most individuals early in life, predominantly at mucosal surfaces after exposure to infected secretions. It has been implicated in a range of diseases including labials and stomatitis, blinding keratitis, and, rarely, encephalitis. According to the data, more than 70% of adults have neutralizing antibodies and serve as reservoirs of the virus. The authors have done an excellent systematic review of the rate of shedding of HSV from the oral cavity. Asymptomatic shedding is generally defined as the presence of HSV in the absence of clinical lesions. Based on this review, the frequency of HSV shedding at virus numbers sufficient to be transmitted are significantly higher than most clinicians would suspect. These high frequencies of asymptomatic shedding suggest that HSV-1 is not as dormant during latency as previously believed. This translates to the fact that even without clinical lesions, the dentist, dental hygienist, and chairside assistant are at risk. This data emphasize the importance of being diligent in maintaining proper infection control procedures (eye protection, gloves, mask) when performing routine dental examinations and procedures. All efforts should be taken to minimize splashes and splatters of oral fluids even in the absence of HSV oral lesions. Also, medical conditions, eg, immunosuppression and traumatic oral surgical procedures, increase the likelihood of virus shedding in the oral cavity.
Howard E. Strassler, DMD
Professor and Director of Operative Dentistry
Department of Endodontics, Prosthodontics and Operative Dentistry
University of Maryland Dental School