North Carolina's COVID-19 metrics are improving even as fewer and fewer people are receiving a vaccine. State health department data released Monday showed unvaccinated residents are far likelier to contract the virus, become hospitalized and die. State health officials warn of a decreased effectiveness of the vaccines in preventing infection from the more contagious delta variant. But the approved COVID-19 shots remains the best prevention measure. In the past two weeks, hospitalizations have dropped by 25%. Cases have declined by more than 30%. The share of tests coming back positive are also dwindling.