Colorado is using tried-and-true get-out-the-vote tactics to boost COVID-19 vaccination rates across the state.Why it matters: The novel approach is part of a broader effort by state public health officials to reach herd immunity by targeting populations that are hesitant or too busy to get vaccinated.Get market news worthy of your time with Axios Markets. Subscribe for free.The backdrop: To boost turnout ahead of an election, a campaign’s get-out-the-vote strategy works like this: Identify the target population. Make contact. And tell them how to go vote.COVID vaccinations have followed a similar path to elections thus far: Die-hard supporters went first, but ultimate success is determined by how many others show up.The state of play: About 33% of Colorado’s population is fully immunized, state data shows, and 45% has received at least one dose. It’s far below the 70%+ needed for broader community protection, and lower rates among communities of color are concerning health officials.Moreover, the number of vaccines administered per week is declining, even as eligibility expands.How it works: Healthier Colorado, an advocacy organization with experience managing ballot initiatives, developed the vaccine turnout campaign and partnered with Gov. Jared Polis’ administration.The nonprofit tapped its political data firm to pull phone numbers for populations who lived near vaccine clinics or those who matched hesitant groups identified by polling data, such as conservatives and rural residents.Trained AmeriCorps volunteers worked phone banks, making calls and sending text messages to help people get vaccine appointments and provide transportation if needed.The volunteers — speaking in English and Spanish — also responded to messages on a vaccine hotline to help people who didn’t have the resources to make appointments.Another tactic: Phone bank volunteers had scripts to address questions about the vaccine and counter misinformation.One script reads: “None of the three vaccines change your genetic code or DNA. The vaccines contain key ingredients that prepare your immune system to fight the virus along with basic ingredients like fats, potassium chloride and sucrose.”What they’re saying: “We were able to have those meaningful conversations with people,” said Kyle Piccola at Healthier Colorado, comparing it to door knocking in a political campaign.By the numbers: The nonprofit spent more than $200,000 on the campaign since its launch in March. So far, it’s making progress, albeit slowly.More than 1,500 appointments were scheduled through the calls, which supported 23 clinics.The average call lasted 10 minutes.The bottom line: In Colorado, GOTV now means “get out the vaccine.”Like this article? Get more from Axios and subscribe to Axios Markets for free.