We had a vaccine for COVID-19 within a year of identifying the virus that causes it, yet still don’t have one for HIV after 40 years of research. Why is that? On this week’s episode, Sam and Deboki cover HIV’s history and spread, how it causes AIDS, and the tiny things it does that have allowed it to evade potential vaccines for decades. For a transcript of the episode, head to: http://www.acs.org/tinymatters