How is HIV transmitted

?Most common mode of transmission

Unprotected vaginal and anal contact, between males or between females and males is the most common mode of acquiring HIV. It is responsible for more than 80% of new HIV infections all over the world. Other common modes are sharing contaminated injections & from infected mother to child.


HIV risk by different types of exposure


The risk might vary slightly among different medical literatures. The percentage between brackets represent the risk of transmission from an infected source without any intervention.

– Contaminated Blood/ organ donation (90 -100%)
– Mother to child transmission (28%)
– Breastfeeding 4-8% depends on the duration
– Sharing needles to inject drugs (0.67%)
– Mucous membrane exposure (0.63%)
– Needle stick injury (0.3%)
Sexual exposure:
– Receptive anal sex (1.11%)
– Insertive anal sex(0.06%)
– Receptive vaginal sex (0.1%)
– Insertive vaginal sex (0.082%)
– Receptive oral sex (0.005%)
– Insertive oral sex (0.01%)

Rare causes (risk is less than 1 in 10,000 exposure)
– Fingerings, fistng, rimming
– Masturbation by partner hand
– Deep kissing with mouth ulcers
– Sharing sex toys
– Human bite , spitting


Body fluids

People can pass HIV through the following body fluids:

– blood

– semen (including pre-cum)

– vaginal fluid

– anal mucus

– breast milk