TAKOMA PARK, Md. (AP) — Companies are struggling to recruit diverse volunteers in final U.S. tests of possible COVID-19 vaccines. Minority enrollment in studies of two shots has inched up in recent weeks, but even more is needed this fall as additional vaccine testing gets underway over the next two months. New recruitment efforts are gearing up, with the help of trusted voices in hard-hit communities of color, such as Spanish-speaking “health promoters” and Black pastors. The outreach is getting a late start. But it’s critical to prove if the vaccines work in all the populations who will need them.