Centers for Disease Control and Prevention

Percent of the total population 65 years and older with an updated (bivalent) booster dose reported to CDC

The predicted winter wave of COVID-19 appears to have arrived in Arizona. The Arizona Department of Health Services reported 10,775 cases in its weekly update Wednesday — more than twice as many as the state reported two weeks ago. And one in five tests performed at public testing sites this week in Arizona turned up a positive case. But most residents are not up-to-date with vaccines.

Updated booster doses that target the highly contagious omicron variant are available to most Americans over age five. Nationwide, uptake has been slow, though. The Centers for Disease Control and Prevention reports only about 12% of U.S. adults have received the new booster since it became available in early September. But Arizona’s rate of uptake is even lower than the national average — only about 10% of adults here are up-to-date, according to the CDC.

Rates of booster uptake among older adults, who are at the highest risk for severe illness or death from COVID-19, are somewhat higher, but still fall short of what public health experts say is needed to control the virus. About 27% of adults over 65 have received the booster nationally, according to the CDC. About 24% of Arizonans over 65 have had the new shot — that’s one of the lowest rates among states.

Medical experts say the new bivalent boosters are important not just for slowing spread of the virus but protecting against its most severe outcomes, including hospitalization and death.

Dozens of Arizonans are still dying from COVID each week. The state health department reported 34 COVID-19 deaths this week and 40 the previous week. But that weekly death toll is staying well below levels seen in previous winter waves. This time last year, as a winter surge began, the state was reporting weekly death tolls about six times higher than it is seeing now.

→ COVID-19 cases are on the rise. Here's how to prepare for an expected surge