Brief Answer: HSV 1 infection following oral sex Detailed Answer: Hello, As you are getting cold sores on your upper lip once or twice in a year from herpes simplex virus 1 (HSV1), it is unlikely for HSV1 to be transmitted to the genitals through oral sex. Having been infected with HSV1, the immune system has already manufactured, and kept on reserve, antibodies to this virus. Whenever the virus is encountered again, the immune system is already well acquainted with its enemy and can initiate a quick and efficient counterattack. On the other hand, for someone who has never had herpes cold sores before, infection with HSV1 through oral sex can result in a true primary episode of genital herpes. But these cold sores can give your sexual partner genital herpes, because the same virus causes both genital herpes and cold sores. Cold sores, which usually appearing on your upper lip are also known as oral herpes and are caused by the herpes simplex virus (HSV). This same virus is also responsible for blisters and sores in the genital area, known as genital herpes. There are two types of HSV, cold sores are usually caused by HSV type 1 and genital herpes are usually caused by HSV type 2. The two herpes viruses are interchangeable. If HSV-1 comes into contact with genital area, your partner can get genital herpes. So if you have HSV-1 then you can spread it to your partner through any type of sexual contact where the mouth comes into contact with the genitals. Also you don't even need to have any outward sign of cold sores to spread the virus. In fact, you're most likely to spread the virus to your sexual partner in the first few days when the blisters are forming. Thank you

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