Expert: Kristen Brannock, MPH - 3/14/2005

Question
I have been doing hiv/aids research.  There is much talk about how kissing does not pose much of a risk of transmission even  deep kissing, yet it is warned not to share toothbrushes, as that DOES pose a risk.  How can both be true.  Kissing would be more direct than a toothbrush I would think.
Would a person have to use the toothbrush RIGHT after the infected person?  Would the blood need to be visible?
I am very confused on how both those can be true. Thanks.

Answer
Kissing does not generally involve blood, which is why it is not considered a route of transmission-saliva does not transmit HIV. However, brushing teeth can involve blood due to tearing the gums which can leave a way for infected blood from one person to enter the body of another. Still, sharing a toothbrush is not a very effective means of transmission. It all depends as to when a person would use the toothbrush in relation to another or how much blood has to be present. The blood would usually be visible, but the important thing is how much virus is present, which cannot be seen.