Hi
It can be difficult to work out the exact way an STI is passed as most of the time an STI shows no symptoms and people usually have different types of sex rather than just one type. Currently the way they work this out is to study the people who get an STI and ask them what types of sex they had. As you can see for some STI it gives us a general idea rather than something precise.
With our chances chart, Hand Job (hand to penis or vulva) it is the risk that both includes giver and receiver. For example if someone had a syphilis or herpes sore on their penis and was given a hand job by someone there is a chance someone could develop a syphilis sore or a herpes sore on their hand. If someone did develop this sore on their hand there is a chance they could pass it to another person if this hand came in contact with someone else’s genitals. The risk we gave covers both the giver and receiver. But given this we don’t see these STI being passed from hand jobs and still recommend hand jobs as one of the safer ways to have sex.
You’re correct that the reason HPV, herpes and syphilis can be passed with condom use is because these can be on areas not covered by the condom and be passed by skin to skin contact. Being passed through oral sex is not so much about the saliva but more about the mouth coming in contact with areas not covered by the condom. If someone receives oral sex were the mouth is only in contact with the area covered by the condom and the condom does not break, I can’t see how an STI could be passed.
Thanks for the question, also let us know if you have any suggestions on how we could do the chances charts differently. As we do not have many categories the not “commonly passed” can mean that there is some chance but depending on the STI and the type of sex that is taking place the odds can vary quite a bit.
Please leave a comment to let us know if this answers your question or if you need more information.
Health Nurse
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