Local health experts are projecting that Colorado could reach herd immunity by the middle of August if people continue to get vaccinated at a high rate, according to a new statewide modeling report released Friday.

Health experts with the University of Colorado the Colorado School of Public Health wrote that in order to reach herd immunity, 80% of the state’s population 65 and under must get the vaccine. Currently, researchers project that 48% of all Coloradans are immune to COVID-19 either due to the vaccine or prior infection.

Although the report gives a glimpse of optimism, it also shows that one in 81 Coloradans currently have COVID-19.

“There are high levels of SARS-CoV-2 infection in Colorado right now, and the unvaccinated, even those under 65, face real risks of infection and, in some cases, hospitalization and death,” said Beth Carlton, an associate professor with the Colorado School of Public Health and a member of the modeling team.

Although an estimated 71,400 Coloradans are currently infected with COVID-19, the overall the number of cases and hospitalizations has declined over the last two weeks.

To keep the numbers down throughout the summer and inch closer to herd immunity in Colorado, experts say vaccination is key. In the report, experts compared high and low rate vaccination rates to create long-term projections for the state.

In the high-rate category, experts assumed 80% of all individuals aged 12 to 64 would receive the vaccine, while in the low-rate scenario they assumed only 62% of people aged 40 to 64 and 50% of people 12 to 39 would receive the vaccine during the same period. Values were estimated based on hesitancy rate surveys in Colorado provided by CDPHE.

Experts found that in the high-rate scenario, 70% of the state’s population would be vaccinated by the middle of August, and hospitalizations would decrease along with new cases of COVID-19.

In the low-rate scenario, there is no timeline for when herd immunity could potentially be achieved. Cases and hospitalizations would continue to decline, but at a slower rate, and researchers project more than 150 additional hospitalizations in July compared to the high-rate scenario.

“This modeling indicates that the course of the epidemic curve into summer depends on the success of vaccinating Coloradans in the weeks ahead,” Colorado Department of Public Health and Environment officials said in a press release unveiling the report.