This topic will be split into 3 parts; Definite ways of HIV transmission, theoretical ways of transmission, and no way of transmission.
Bear in mind that in order for HIV to be transmitted fluid from a positive person has to come into contact with the negative person. Semen and blood hold high loads of the virus but saliva and vaginal fluid hold very little.
Definite ways of HIV transmission (risk will be listed as risk per 10000 – so 1/10000 means that for every 10000 people who engage in that activity, 1 person will become infected.
- Blood transfusion – 9250/10000 (this is only with HIV infected blood which is very rare nowadays as every donor blood sample is screened before use).
- Needle sharing in intravenous drug use – 63/10000.
- Needlestick injury – 23/10000.
- Receptive anal sexual intercourse – 138/10000.
- Insertive anal sexual intercourse – 11/10000
- Receptive penile-vaginal sexual intercourse – 8/10000
- Insertive penile-vaginal sexual intercourse – 4/10000
- Receptive and insertive oral sexual intercourse – low (too low for accurate numbers).
Theoretical ways of HIV transmission:
- Blood contact onto an open wound – possible but an unlikely scenario as open wounds should be tended immediately in order to reduce the risk of other infections. The risk of a bacterial infection would be higher than an HIV infection.
- Blood contact onto mouth or eyes – again possible but extremely unlikely unless you happen to be in a horror movie.
- Dried blood – although HIV can survive in dried blood for several days, the environment has to be favourable and transfer this way is very very unlikely.
No risk of HIV transmission:
- Breathing the same air as someone.
- Touching a toilet seat or door knob.
- Drinking from a water fountain.
- Hugging, kissing or shaking hands (although kissing may transfer fluids the level of virus in saliva is so low as to make the risk negligible).
- Sharing utensils.
- Sharing gym equipment.
- Skin to skin contact with an HIV positive person even if they happen to have fluid of unknown origin on them (particularly applies to commercial sex workers).
- Biting or scratching that does not break the skin or draw blood.
- Essentially, as mentioned above, fluid-fluid contact is necessary for transmission – if this hasn’t happened then there is no risk for HIV.
I hope this helps answer most questions that concern people over possible ways of HIV transmission – if new questions pop up I will try and add to this topic to help allay people’s fears.