Can a person get infected with HIV by kissing?

Q: I am a 24 years old man and have kissed my girlfriend a number of times for 4-5 minutes each. Last month she tested positive for HIV. What are my chances of getting infected with HIV? For how long has my girlfriend been infected with HIV?

A:Kissing, which involves the possibility of saliva exchange, does carry a risk of HIV infection from the infected to the non-infected. However, the risk from kissing, even when the tongue is inserted in the partner’s mouth has a relatively low risk compared to other sexual activities. There is no easy way of determining when a person was infected – in very general terms you can be certain that the risk behaviour was at least 6 weeks earlier and possibly 3 months ago as the window period is 6 to 12 weeks. This is the period when the person has got infection but the test is still negative.