Grand Forks County is about 50% of the way to herd immunity, but vaccine hesitancy could be a challenge The number of people in northeastern North Dakota who indicated that they were unwilling to receive a COVID-19 vaccine could shrink the figurative pool of people Grand Forks County public health workers hope to vaccinate to achieve herd immunity. 9:35 pm, Apr. 19, 2021 × The large number of people who have said they are skeptical of a COVID-19 vaccine means Grand Forks County is approaching a ceiling of sorts as public health workers seek to achieve herd immunity. A total of 21,368 county residents have been fully vaccinated as of Friday, April 16, according to data presented to Grand Forks City Council members on Monday. That’s more than halfway to the mark that public health workers believe they need to achieve herd immunity, which would mean the virus, in effect, runs out of room to spread.