A subdermal implant that delivers the HIV antiretroviral tenofovir alafenamide (TAF) has shown promise as an alternative to daily pre-exposure prophylaxis (PrEP) in an animal study. Publishing their findings in Antimicrobial Agents and Chemotherapy, researchers implanted the matchstick-size device in beagle dogs and tested its ability to deliver TAF over a 40-day period.