Of course you cannot know whether it was the Valtrex that prevented transmission to your partner, or just luck. But the drug is completely benign, i.e. virtually no side effects. There is no reason to stop taking it if it seem to be helping.
HHH, MD
n=1
I was in a relationship for four years in which I used Valtrex and we did not use condoms. My partner was tested a couple of months after our break-up and was found to be negative for HSV-2.
But I'm someone who does well with chronic suppressive therapy - I have never had an outbreak, ever, while taking Valtrex. And it was apparently successful in helping to protect my last long-term partner.
50% is the minimum effectiveness of antiviral therapy; it's probably closer to 70-80%. (The research study was biased toward underestimating the real level of protection.) And condoms are also more effective than 50%, maybe 90% or higher. Most couples discordant for HSV-2 who avoid sex when symptomatic, use condoms consistently, and take antiviral therapy probably can expect to have sex many years, perhaps indefinitely, without much chance of transmission.
HHH, MD
Unfortunately, there are no available data on risk of HSV-2 transmission by cunnilingus. However, based on clinical experience, it appears to be uncommon--and must be exceedingly rare when the infected person is taking antiherpetic therapy.
The risk of transmission for vaginal intercourse when both antiherpetic therapy and condoms are used undoubtedly is much lower than 1-2% per year. Where did you get that figure? With neither condoms nor drug, the annual risk averages 3-5%, and the combination of condoms plus antiherpetic therapy probably reduce that risk by over 90%.
Bottom line: I would avoid cunnilingus when the infected person has visible or symptomatic herpes lesions, but otherwise wouldn't worry about it.
Good luck-- HHH, MD
I'm just curious. My husband and I are doing oral sex and we're both first timers to each other. Is it still dangerous to do cunnilinggus* even if we're both clean? Are we safe from having STI?
Doc,
From everything I've read, it seems that antiherpetic therapy lowers the risk by 50% (from 4% to 2% transmission risk/year) and condoms lower that risk by an additional 50% (from 2% to 1% transmission risk/year).
Hence, assuming a 4% chance of transmission/year, with daily valtrex and consistent condom usage, that risk goes down to 1% per year. Does this sound right?