Hi! I was crossing the street and I was in a rush...I smacked absentmindedly at the crossing button which had a metal arrow embossed on it (for the visually impaired). It had a sharp corner, which cut the tip of my finger. I crossed the street and looked at my cut and it bled some. I washed it off and it sealed up almost instantly. I started thinking about all the people that touch the button and whether I could have contracted anything. No one had touched the button in the minute or so while I was walking up, and I was really careful to go back and check to see if anything was coating the button (it was obvious fluids or blood on it). It is also out in the open, not quite in direct sun but there was a lot of light.

I understand the transmission equation...but I am hoping someone can PLEASE confirm that this is a no-risk episode? I know you're very busy, but it would help me immensely if anyone could respond.

Hello and thank you for your inquiry.

We understand that you would like confirmation that cutting your finger on a crossing button does not put you at risk of an HIV infection. We can confirm that this is a No Risk situation, meaning transmission of HIV is not possible in the given scenario.

Although you say you understand the transmission equation, I will review it for others who are not familiar.

In order for an HIV transmission to occur, all three of the following conditions must be met:

1 - There must be HIV present in a bodily fluid. The five bodily fluids that carry the HIV virus include: blood, semen (including pre-ejaculate), vaginal fluids, breast milk, and rectal secretions. (1)

2 - The bodily fluid containing HIV must have direct access to the bloodstream. This can be through cuts, tears, rips, mucous membranes, open sores, or needles. (1)

3 - Transmission occurs through a risky activity in which the first two conditions are met. (1) Unprotected vaginal and anal sex, and sharing hypodermic needles for injection drug use are two examples of risky activities for transmission of HIV.

Your scenario does not meet these three conditions.

Regarding the presence of HIV on environmental surfaces, scientists and medical authorities agree that HIV does not survive well in the environment. To obtain data on the survival of HIV, laboratory studies have required the use of artificially
high concentrations of laboratory-grown virus. Although these unnatural concentrations of HIV can be kept alive for days or even weeks under precisely controlled and limited laboratory conditions, CDC studies have shown
that drying of even these high concentrations of HIV reduces the amount of infectious virus by 90 to 99 percent within several hours. Since the HIV concentrations used in laboratory studies are much higher than those actually found in blood or other specimens, drying of HIV infected human blood or other body fluids reduces the risk of environmental transmission to that which has been observed — essentially zero.(2)

Results from laboratory studies should not be used to assess specific personal risk of infection because the amount of virus studied is not found in human specimens or elsewhere in nature, and no one has been identified as infected with HIV due to contact with an environmental surface. Additionally, HIV is unable to reproduce outside its living host (unlike many bacteria or fungi, which may do so under suitable conditions), except under laboratory conditions; therefore, it does not spread or maintain infectiousness outside its host. (2)

Recommendation: No need for HIV test with the scenario provided, refer to a physician for other health related questions.

AIDS Vancouver Helpline Volunteer, Dyson

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