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Small-Scale Question Sunday for September 8, 2024

Do you have a dumb question that you're kind of embarrassed to ask in the main thread? Is there something you're just not sure about?

This is your opportunity to ask questions. No question too simple or too silly.

Culture war topics are accepted, and proposals for a better intro post are appreciated.

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What follows was learned over a decade ago in microbiology class and may be out of date.

HIV exclusively infects cells of the immune system through a handful of receptors, none of which are expressed on the mucosa of the anus/vaginal tissue. As a consequence, it needs to penetrate multiple layers of mucus and epithelial tissue before it can reach a cell that it can productively (use to produce more viral particles) infect. Anal sex generates microtears in the mucosa much more readily than vaginal sex and provides more opportunities for the virus to reach the bloodstream/immune tissues. There was also some speculation about 'sensor' immune cells that reach into the epithelium that may also act as a route for infection, but I'm skeptical.

What shocked me in that class was just how rare transmission was; you can see the numbers in the table morgenland linked. Made me think that you have to be either extremely unlucky, extremely promiscuous or just stupid/desperate enough to share needles to get infected.