COVID-19 vaccine providers and local health officials are concerned about the drop in demand for the shots, as mask rules relax throughout the Tri-State region.
"If we don't step up and get vaccinated, or if certain sectors of communities don't get vaccinated, the virus can run rampant in those sectors," said Suzi Francis, ambulatory clinical pharmacy manager at St. Elizabeth's Hospital.
In Northern Kentucky, less than one third of the population is fully vaccinated. Ohio counties range from 21% to 42%.
Clinics open to walk-ins remain busy, but there are signs that demand is trailing off.
"We are filling our appointments, but it is taking a little bit longer," said Francis. "I think we're to the population that hasn't seen as much of the personal devastation that COVID could cause or they feel like they're safer because they're younger."
People in their 20s have more active COVID-19 cases than any other age group in Northern Kentucky, Ohio and Indiana.
As schools and universities approach summer break and mask restrictions and capacity limits relax region-wide, health officials worry that more contagious or severe variants of the virus could become an issue in unvaccinated groups.
"I think this is important, when you make that decision, when you're thinking your hesitancy, saying 'well I made it this far, I might as well not bother with it,'" said Dr. Carl Fichtenbaum, professor of infectious diseases at UC College of Medicine. "That would be true if the virus wasn't changing. But with the virus changing and adapting to its environment, you have to change and adapt too."
Until herd immunity is achieved, health officials expect virus mutations to continue increasing the likelihood of necessary booster shots for those who have already been vaccinated.