From The New Yorker By Dhruv Khullar February 2, 2021 C.N.A.s have questions about the speed of vaccine development, the immunity it confers, long-term side effects, and what could happen if the virus mutates further.Photograph by Yuki Iwamura / Reuters Tiffany Chance has worked as a certified nursing assistant since 2005. As an African-American woman...