Close icon Two crossed lines that form an 'X'. It indicates a way to close an interaction, or dismiss a notification. At a mass vaccination site set up in a California Six Flags, a nurse administers the COVID vaccine. Jae C. Hong/AP Photo North Dakota and South Dakota are two of the states doing the best job at distributing coronavirus vaccines. Despite an uneven nationwide rollout, they've excelled due to centralized storage and vaccination sites. Flexibility and collaboration between health systems has been key to getting approximately 80% of delivered vaccines into arms. North Dakota and South Dakota are among the US states doing the best job of rolling out coronavirus vaccines, and their experience could provide valuable lessons as the rest of the country struggles to catch up.