The Biden administration says a third dose of vaccines for all American adults will end the pandemic faster. And experts say there is evidence of waning vaccine effectiveness against mild-to-moderate disease. But globally, what’s the best use of the next available dose?  Guest: Saad Omer, director of the Yale Institute for Global Health.  Host: Lizzie O’Leary This episode was produced by Alyssa Edes. Learn more about your ad choices. Visit megaphone.fm/adchoices