USA TODAY If you've been waiting for a big national campaign telling you COVID-19 vaccines are safe and everybody should get them, don't hold your breath. Until the supply is plentiful, the federal effort is largely focused on minority communities hesitant about the immunizations. It's a wise approach, experts say. The kind of one-size-fits-all public service announcements that once blanketed the country won't work for COVID-19 vaccines, they say. Those were for universal messages – only you can prevent forest fires, keep America beautiful, friends don't let friends drive drunk. With COVID-19, different communities need different messages, and mass advertising doesn't necessarily make sense, said Hal Hershfield, a professor of behavioral decision-making at the University of California-Los Angeles Anderson School of Management.