Young, unvaccinated people are showing up at hospitals with Covid-19 — in some cases being admitted to intensive care and put on ventilators — in disturbing numbers, health officials across the country have warned.

Vaccination rates among younger people are lower than among older Americans, according to the Centers for Disease Control and Prevention. The agency's data show that slightly fewer than half of people in the U.S. ages 18 to 24 and 25 to 39 are fully vaccinated. The number is even lower for children 12 to 18, who have been eligible to be vaccinated for months.

Officials urge younger people to roll up their sleeves and get the shots.

"Please be safe and if you are 12 or older — please protect yourself," read a tweet by Dr. Thomas Dobbs, Mississippi's health officer.