Starting March 5, Coloradans aged 60 and up can start getting COVID-19 vaccine David Zalubowski/AP and last updated 2021-03-01 09:50:56-05 COLORADO SPRINGS â Starting March 5, Coloradans who fall in Phase 1B.3 of the vaccine roll-out will become eligible to get a vaccine. On Friday Gov. Polis announced an update to the COVID-19 vaccine prioritization lists. Updated Phase 1B.3 List: Coloradans 16-59 with two or more comorbidities Additionally, the governor said Phase 1B.4 will go in effect by the end of March. There will be an update next week on what date Phase 1B.4 will start. The governor said he estimates it may be around March 21.