Here's a fascinating new finding in HIV research:

Over 80% of HIV infections are acquired through sexual intercourse, primarily via semen from HIV-positive men. Pilcher says that researchers have been studying the role of semen in HIV transmission, but have focused primarily on the quantity and type of virus contained in semen. "We’ve looked at everything except the semen itself," he says.

Now researchers have found that peptides clustered together into long fibres may be more important for HIV transmission than viral load. “If that’s true, then we’ve been looking at the wrong thing for a long time,” says Pilcher.

This is potentially big news. If we can figure out a way to prevent HIV from binding to the fibres, we can make men with HIV much less infectious. Increasingly that's the most feasible key to restraining the epidemic. It seems to me that as treatment renders HIV more and more manageable, fear of illness and death has inevitably become less salient as a means of prevention. Men will always want to have sex and will always take risks to get it. That's simply human nature. You can alter this temporarily but not permanently. So the key to halting HIV is to make it harder to transmit. I've long believed that the search for a vaccine is futile, and we've just gotten more information on why. Reducing the viral loads of treated individuals through anti-retroviral therapy helps - but this new finding could really shift the balance. yes, much more work needs to be done to see if this pans out. But remember: just small downticks in infection rates can have a big impact in the course of an epidemic. The more we learn ...

Hat tip: 3Q.

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