Pima County health officials warned this week that COVID cases are rising among children 11 and under—a population that remains ineligible for vaccines.

The increase comes about a month after most schools reopened for the fall semester, leading to an increase in cases by 16.5% over the last week.

Kids between 12 and 19 had COVID case growth of 11.7%, said Pima County Chief Medical Officer Dr. Francisco Garcia. The FDA authorized the Pfizer COVID vaccine to be offered to children 12 and older on May 10, expanding possible vaccination coverage in Pima County.

Garcia reported that 73.1% of vaccine-eligible populations (12 and older) have at least one dose of vaccine.

Garcia said the greatest rise in reported COVID cases came from young and middle aged adults.

“We see the greatest growth in this middle age group 20 to 44, there were 858 additional cases, representing 41% of the total cases from one week to the next,” Garcia said.

Garcia’s assessment was echoed by Banner Health Chief Clinical Officer Dr. Marjorie Bessel, who said that a majority of COVID patients at Banner Health are in the 20 to 65 age group—and 90% are unvaccinated.

Bessel asked the public to consider getting the vaccine even if they had COVID once before.

“Studies have shown that reinfection rates are 2.34 times more likely in those who remain unvaccinated, which is why vaccination is still recommended by the CDC and medical community even if you’ve had COVID,” Bessel said.

Getting the vaccine is especially important as the Delta variant takes America by storm. Bessel reported that the Delta variant accounts for 99.1% of all coronavirus circulating in the United States.

Ahead of Labor Day weekend, Garcia advised the public to wear a mask indoors and while traveling. He also advised that unvaccinated residents should not travel. 

“This pandemic has become one of the unvaccinated, and I sincerely hope that Banner and others in the medical community will be able to persuade those who have not yet been vaccinated,” Bessel said.