Because there is a risk that someone will accidentally relate it, after reading your confusion of two index causes with the word needle, in the way I remain convinced you are supporting.

The rate of conversion from exposure to HIV + blood is of the order of 0.3% according to the occy health info I am looking at. PEP (prophylaxis) can reduce this by an even larger factor. A study quoted on our page reckons by 80% but that is just one study. Of the 255 needle sticks in the 1997 to 1999 study, one had seroconversion, which will be the one you refer to. We are both reporting both a success story and same figures. However, the accuracy of voluntary submission data has on average a tolerance factor of 15% which with such small figures makes complacency dangerous.

Needle stick testing is usually regardless of knowledge of contamination unless the blood is from a known to be negative source, although Hepatitis being a co factor, most wish the tests to be done. Even fucking important mandarins can end up tested. I was attacked with a syringe needle during a review of a sectioned patient when I was carrying out such duties for MHAC. Assurances that he was "clean" don't cut it at the time.

Working out how a sex worker worker who shoots up contracted it isn't quite so easy without contact tracing. A bit like wondering which baked bean caused that last fart. Another statistical caution to add to the list of your definitive data.