Protecting Uninfected Partners
Important Results from a New Study
The 2004 publication of the results of a major scientific study on genital herpes has given new hope to couples in which one partner has herpes and the other does not. In January, 2004, in the New England Journal of Medicine, the results of a multicenter, randomized, clinical trial was published. This landmark study has offered new hope to these “discordant” couples, in which person has genital herpes and the other does not.
It is known that partners infected with genital herpes can transmit the infection to an uninfected partner BOTH when symptoms are present (such as redness and blisters) as well as when no symptoms are present (called “asymptomatic shedding”; see the paper on Asymptomatic Shedding at www.herpes.org ). Researchers have shown that viral shedding of herpes virus occurs very often from the genitals of the infected partner even when the infected partner has no symptoms: In some cases over 80% of the time. This means that an infected partner can transmit herpes to the uninfected partner even when no symptoms are present.
Wald et al, as well as other authors, have previously described on many occasions that the use of an antiviral compound such as Valtrex or acyclovir promptly decreased the incidence of viral shedding, reducing the shedding by over 80% in many cases. This profound reduction of viral particles was so significant that it made sense to do a research study to see if, indeed, that fewer uninfected partners became infected when the infected partner took antiviral medication regularly.
This important study enrolled 1484 discordant couples (again, “discordant” means that one partner had genital herpes and the other did not). The study ran for eight months. With half of the couples the infected partner took Valtrex, and in the other half the infected partner took placebo. The results were vitally important to discordant couples.
The research team found that infections developed in the uninfected partner in only 4 of the 743 couples in which the infected partner took Valtrex, whereas 16 of 741 uninfected partners developed the infection when placebo was taken. This was a reduction in risk to the uninfected partners of about 50%, when the statistics were examined. Viral shedding was reduced by about 70% when Valtrex was taken.
Close examination of the data indicates another important point. When partners wore condoms during intimate contact WHILE the infected partner took Valtrex every day, then only a single uninfected partner developed genital herpes. This, I think, is a very important take home point.
Discordant couples should discuss whether the infected partner should take antiviral therapy. These results give scientific proof that a discordant couple that approaches intimate contact with care can protect the uninfected partner to a very high degree. As the data prove, the results suggest that the chance of the uninfected partner becoming infected is reduced from 8 incidences per 220 couples that nearly always wore condoms but NO Valtrex (about a 4% chance overall) to 1 incidence in 223 couples that nearly always wore condoms and Valtrex WAS taken daily (about a 0.4% chance).
So, if the infected partner takes DAILY Valtrex AND the couple “nearly always” uses condoms, as well as avoiding intimate contact if any symptoms are present, the risk of contracting genital herpes during an eight month period goes from about four chances in a hundred all the way down to 4 chances in a thousand. This is a 90% risk reduction from NOT using medication and NOT using condoms.
By the way, Valtrex is the drug that was studied in this case. Would other antivirals work, such as Famvir or generic acyclovir? We do know that viral shedding is also reduced for acyclovir. However, the pharmacokinetics of Valtrex show that it generates a four hundred percent higher level of acyclovir in the bloodstream than does generic acyclovir (Valtrex turns INTO acyclovir once it is absorbed). Thus, it is possible that Valtrex is a superior drug and might have greater protection. This study did not look at the other drugs, and chances are that such a study might not be undertaken, given the enormous cost of conducting this research.
Finally, REMEMBER!! This study only looked at people who took the medication every single day during the study. There is NO PROOF that taking a pill right before intercourse – or for a few days before intimate contact – offers ANY protection to the uninfected partner at this time. Perhaps such a study will be done one day, but for now, to offer the best chance to the uninfected partner, then the infected partner must take the medication every day.
As with all medical information, persons with herpes infections and their partners should make ALL medical decisions together with an informed and caring physician so that the right care is given.
CONCLUSION: This important work sends a very clear message. As Corey et al pointed out in a recent edition of Herpes magazine, “the International Herpes Management Forum (IHMF) now recommends that physicians offer suppressive valaciclovir therapy to immunocompetent individuals concerned about transmitting genital herpes to a heterosexual partner, and advises safer sex behaviour, including the use of condoms, to prevent genital herpes transmission.”2
1. Corey L, Wald A, Patel R, Sacks SL, Tyring SK, Warren T, Douglas JM Jr, Paavonen J, Morrow RA, Beutner KR, Stratchounsky LS, Mertz G, Keene ON, Watson HA, Tait D, Vargas-Cortes M; Valacyclovir HSV Transmission Study Group. Once-daily valacyclovir to reduce the risk of transmission of genital herpes. N Engl J Med. 2004 Jan 1;350(1):11-20. Department of Medicine, University of Washington, Seattle, USA. email@example.com
2. Corey L, Ashley R. Prevention of herpes simplex virus type 2 transmission with antiviral therapy. Herpes. 2004 Aug;11 Suppl 3:170A-4A. Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, 03-100, PO Box 19024, Seattle, Washington, 98109-1024, USA. E-mail: LCorey@u.washington.edu
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