CEDAR RAPIDS — Appointment slots are still open on a mass COVID-19 vaccine clinic that will take place next week in Cedar Rapids, which aims to reach vulnerable populations in the area.The clinic — which is hosted by the Cedar Rapids NAACP — aims to reach people of color, who have been disproportionately impacted by the pandemic and often face additional barriers to getting the COVID-19 shot, advocates say.“If someone wants the shot, we’re trying to do our best to make sure the vaccine is available to them and that they don’t have to wait a long period of time,” said Dedric Doolin, president of the Cedar Rapids NAACP.