Thank you for your inquiry. From what we gather from the question, you were asking about the possibility of HIV transmission from your son touching a public restroom toilet seat with his hand and then touching his eye.
From the information given, this scenario is determined to be of No Risk (transmission is not possible in the given scenario). This scenario is determined to be of No Risk because it does not fulfill the requirements of our HIV Transmission Equation (see image below).
In order for HIV transmission to occur, HIV positive fluid (blood, semen, vaginal fluid, anal fluid, breastmilk) must have direct access to the bloodstream through a high, low, or sometimes negligible Risk activity.
Although you mention the possible presence of blood, there is no direct access to the bloodstream in this scenario. Additionally, the blood you have described on the toilet seat would have been exposed to oxygen, rendering HIV transmission nearly impossible. Dried or drying HIV positive fluid that is exposed to the environment such as on top of toilet seat is quickly rendered inactive, effectively making transmission difficult to achieve (1) (2).
Recommendation: No need for HIV testing with the scenario provided, refer to a healthcare professional for other health related questions.
We sympathize with the anxieties of becoming a new mother (congratulations!) and we hope to have eased some of your worries.
AIDS Vancouver Helpline/Online, Nancy.
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