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How communicable is Herpes during incubation period?
May 11, 2009 5:16 PM   Subscribe

How herpes is infectious during the incubation period?

I had sex with someone who has herpes. Then I had sex with someone else within 24 hours. Condoms were used twice, but I know that are not 100% effective when it comes to herpes. I take showers twice and washed carefully between myself, where nothing else on my skin surface is a problem.

This happened recently, so I do not know if I'm still infected, Herpes has a period of 4-7 days of incubation first first symptoms appear.

It is infectious during the first few days or so?

Do not worry, I have the communication, shitting-my-pants, and I-am-a-bastard-idiot of this situation under control, I just have not been able to find the answer to this particular issue.

Thank you.
posted by anonymous to Health & Fitness (7 answers total)
Possible? Sure. Likely? Barely even a little bit. Unless the first person you were with was having an outbreak or about to have an outbreak your chances of contracting the virus are very small (in the low single digit percentage points). To then go on to infect someone else within 24 hours is almost incomprehensible, especially if you showered in between.

You're not a bastard... this is herpes, not HIV. Most of the adult population already has it. Relax.
posted by telegraph at 5:50 PM on May 11, 2009

You're not a bastard... this is herpes, not HIV. Most of the adult population already has it. Relax.

Um, no. Not everyone has it and the poster should not relax.

I assume you're referring to genital herpes.
posted by anniecat at 5:56 PM on May 11, 2009 [2 favorites]

Despite what the TV commercials would have you believe, it's pretty unusual to spread it when you aren't near an outbreak.
posted by small_ruminant at 5:56 PM on May 11, 2009

anniecat - Correct, I should clarify. About 20% of US adolescents and adults have genital herpes. However, about 60% of the US population has oral herpes. If you are already infected with a herpes simplex virus (type 1 or 2, either can cause oral outbreaks), the odds of taking on another HSV, or the same virus in a different area of the body (ie the genitals) are drastically reduced. Which is to say, most American adults either already have genital herpes, or have a virus that makes it even more extraordinary difficult to contract genital herpes.

Finally, for the sake of completeness, I'd like to point out that it's estimated that a huge proportion of HSV infections are completely asymptomatic in the individual, but can still be transmitted and cause outbreaks in the recipient.
posted by telegraph at 6:08 PM on May 11, 2009

First, you would have to be infected which is totally possible even with a condom, but infection is difficult if you don't have an open sore or exposed "moist membranes" like the urethra, vaginal canal, or anus. But don't ignore the raw rubbed flesh that can result from intercourse. The virus won't live long on your skin even if you hadn't showered, which was a good call. Then the virus needs to start replicating which can take some time, but can absolutely occur within the time frame you mention. Then you'd have to pass it again, in this time frame, from the area of infection. Again using a condom was a great idea, but isn't fool proof. I'm not an epidemiologist, but you're probably looking at a very unlikely, but entirely possible transmission to the second partner.

Most of the adult population has been exposed to HSV-1 or "oral herpes" the virus that commonly causes cold sores. Not so much with HSV-2. However, people can be infected by HSV-1 or HSV-2 (the STD) anywhere on their body.

I haven't read any studies on reduced infection rate of a second virus species after exposure to a first species, so I can't comment on that, other than to say I'd love to read a study that supported that claim. And yes, herpes infections anywhere can be almost or entirely asymptomatic in one person, but you did the right thing by communicating with your partners because no one knows how any one individual will react to the virus.
posted by Science! at 6:28 PM on May 11, 2009

Yeah, Science! has it. HSV doesn't live for very long outside of the host, but it will begin replicating pretty quickly, and it's possible that some of your cells had been infected in the first sexual encounter and subsequently produced enough virus for successful transmission to the second partner, albeit unlikely (especially with condoms involved in both cases).

Also worth keeping in mind. A lot of people are asymptotic following HSV infection. Which means you will need to get yourself tested to be sure if you've been infected. You can't rely on symptoms to tell you this.

I haven't read any studies on reduced infection rate of a second virus species after exposure to a first species, so I can't comment on that, other than to say I'd love to read a study that supported that claim.

Previous HSV-1 infection did not reduce the rate of HSV-2 infection, but it did increase the likelihood of asymptomatic seroconversion, as compared with symptomatic seroconversion, by a factor of 2.6 (P<0>
posted by kisch mokusch at 12:52 AM on May 12, 2009

In tissue culture, where conditions are kind of optimized for efficient infection, it takes 18-24 hrs (depending on the cell type) for HSV to complete a round of replication, with that period of time probably swinging more towards 24 hrs in cells still attached to you. For most of the period between when you would have been initially exposed/infected and the point where the virus has replicated itself, there is no infectious virus to be found because it is necessary for the virus to completely disassemble itself in order to replicate (if you look it up, this is called the "eclipse phase" of replication). It is going to take 4-7 days for you to notice any outward signs of infection because it is going to take that many rounds of replication to generate enough virus to really spread among the cells in your body. Thus, if you washed everything off between partners and it really was within 24 hrs, I would guess that the second partner probably doesn't have as much to worry about as you do. I suppose it is within the realm of possibility that the second person was infected by you, but having just watched an HSV take several days to spread among a monolayer and being in the midst of performing a bunch of time course experiments, I doubt it.
posted by The Bishop of Turkey at 5:41 AM on May 12, 2009

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