It’s not common that people diagnosed with HIV, medically trace how they contracted it. Often, narrowing down possible transmission relies on memory and self-perceived situations where transmission could have happened. People who get tested for HIV regularly may have a shorter window of time between their last negative result and their current positive result, which can be helpful in narrowing down exposures.
HIV has a few different strains, but these strains can move through both sexual contact or shared needles. So even knowing your strain may not help you narrow down how you contracted it. There are also many people who have multiple possible exposures either with more than one sexual partner since their last negative HIV test, or becuase they are sexually active and have shared needles during the same period of time.
So to boil it down: no, it’s often not possible to determine for certain how someone contracted HIV.
Please know that regardless of how someone has contracted HIV, the Manitoba HIV program aims to support people, protect their health, and prevent future transmission. Please talk to your HIV health care team or Nine Circles Community Health Centre for more information.
(Just for your interest: There are genetic sequencing tests which have been used in research settings to confirm the origin of an infection, but these are not used when diagnosing someone with HIV. If you are curious about these research studies (which have confirmed that sustained undetectable viral load means HIV cannot be passed to sexual partners) you can read more about them here.)