Nate Mendel

When a person tests positive for HIV, it is not a test for the virus itself but for antibodies to the virus, and the test is not able to distinguish between HIV antibodies and a multitude of other antibodies. Many conditions can lead to a false positive result, including flu shots, hepatitis, and pregnancy.

It's worth noting that invoking God as the entity who set our universe in motion isn't contradicted by the data. Of course, scientists would say the supreme being hypothesis is faith, and outside the realm of science - that it's not amenable to experiment. But we currently have the same problem with the notion of parallel universes.