ProPublica is a nonprofit newsroom that investigates abuses of power. Sign up to receive as soon as they’re published.This story was co-published with NPR.When Mai Yang is looking for a patient, she travels light. She dresses deliberately — not too formal, so she won’t be mistaken for a police officer; not too casual, so people will look past her tiny 4-foot-10 stature and youthful face and trust her with sensitive health information. Always, she wears closed-toed shoes, “just in case I need to run.”Yang carries a stack of cards issued by the Centers for Disease Control and Prevention that...…ProPublica is a nonprofit newsroom that investigates abuses of power. Sign up to receive as soon as they’re published.This story was co-published with NPR.When Mai Yang is looking for a patient, she travels light. She dresses deliberately — not too formal, so she won’t be mistaken for a police officer; not too casual, so people will look past her tiny 4-foot-10 stature and youthful face and trust her with sensitive health information. Always, she wears closed-toed shoes, “just in case I need to run.”Yang carries a stack of cards issued by the Centers for Disease Control and Prevention that...WW…